Congenital hearing loss: a literature review of the genetic etiology in a Mexican population.

Hearing loss is the most frequent sensory disorder, with an incidence of 1:1500 live newborns. In more than 50% of patients, it is associated with a genetic cause, while in up to 30% of cases, it is related to syndromic entities. We performed a literature review of studies on congenital hearing loss of genetic origin in the Mexican population. We identified eight reports that showed that the pathogenic variants most frequently associated with hearing loss are related to the GJB2 gene, although in a low percentage (3%). Other mutations were identified in the GJB6, SLC26A4, or CHD23 genes. On this basis, a possible diagnostic strategy in Mexican patients with hearing loss is to consider an initial screening of these three genes. If these genes were negative for pathogenic variants, the following steps would be to consider second-generation sequencing analysis focused on panels of genes associated with hearing loss, isolated or syndromic, and if necessary, to perform exome or whole-genome analysis. Establishing an etiologic cause is critical in clinically evaluating patients with congenital hearing loss and their families. It can help determine rehabilitation strategies, such as hearing aids or cochlear implants and provide information on disease progression and genetic counseling in this population.

La pérdida auditiva es la alteración sensorial más frecuente, con una incidencia de 1:1500 recién nacidos vivos. En más del 50% de los pacientes se asocia con una causa genética, mientras que en más del 30% de los casos se asocia con entidades sindrómicas. Se llevó a cabo una revisión de la literatura de las investigaciones sobre la pérdida auditiva congénita de origen genético en la población mexicana. Se identificaron ocho reportes en los que se demostró que las variantes patogénicas más frecuentemente asociadas con pérdida auditiva se encuentran en el gen GJB2, aunque en un porcentaje bajo (3%). Se identificaron otras mutaciones en los genes GJB6, SLC26A4 o CHD23. Con base en esta información, una posible estrategia diagnóstica en pacientes mexicanos con pérdida auditiva es considerar un primer paso en el tamiz diagnóstico con los tres genes mencionados. Si estos genes fueran negativos para variantes patogénicas, el siguiente paso sería considerar el análisis por secuenciación de segunda generación enfocado en paneles de genes asociados con pérdida auditiva, tanto aislada como sindrómica, y en caso necesario, realizar el análisis del exoma o del genoma completo. Establecer una causa etiológica es un componente crítico en la evaluación clínica de los pacientes con pérdida auditiva congénita, ya que puede ayudar a determinar las estrategias de manejo y rehabilitación, como el uso de auxiliares auditivos o implantes cocleares, proporcionar información sobre la progresión de la enfermedad y dar asesoramiento genético en esta población.

Congenital hearing loss: a literature review of the genetic etiology in a Mexican population / Pérdida auditiva congénita: revisión de la etiología genética en la población mexicana

Abstract Hearing loss is the most frequent sensory disorder, with an incidence of 1:1500 live newborns. In more than 50% of patients, it is associated with a genetic cause, while in up to 30% of cases, it is related to syndromic entities. We performed a literature review of studies on congenital hearing loss of genetic origin in the Mexican population. We identified eight reports that showed that the pathogenic variants most frequently associated with hearing loss are related to the GJB2 gene, although in a low percentage (3%). Other mutations were identified in the GJB6, SLC26A4, or CHD23 genes. On this basis, a possible diagnostic strategy in Mexican patients with hearing loss is to consider an initial screening of these three genes. If these genes were negative for pathogenic variants, the following steps would be to consider second-generation sequencing analysis focused on panels of genes associated with hearing loss, isolated or syndromic, and if necessary, to perform exome or whole-genome analysis. Establishing an etiologic cause is critical in clinically evaluating patients with congenital hearing loss and their families. It can help determine rehabilitation strategies, such as hearing aids or cochlear implants and provide information on disease progression and genetic counseling in this population.

Resumen La pérdida auditiva es la alteración sensorial más frecuente, con una incidencia de 1:1500 recién nacidos vivos. En más del 50% de los pacientes se asocia con una causa genética, mientras que en más del 30% de los casos se asocia con entidades sindrómicas. Se llevó a cabo una revisión de la literatura de las investigaciones sobre la pérdida auditiva congénita de origen genético en la población mexicana. Se identificaron ocho reportes en los que se demostró que las variantes patogénicas más frecuentemente asociadas con pérdida auditiva se encuentran en el gen GJB2, aunque en un porcentaje bajo (3%). Se identificaron otras mutaciones en los genes GJB6, SLC26A4 o CHD23. Con base en esta información, una posible estrategia diagnóstica en pacientes mexicanos con pérdida auditiva es considerar un primer paso en el tamiz diagnóstico con los tres genes mencionados. Si estos genes fueran negativos para variantes patogénicas, el siguiente paso sería considerar el análisis por secuenciación de segunda generación enfocado en paneles de genes asociados con pérdida auditiva, tanto aislada como sindrómica, y en caso necesario, realizar el análisis del exoma o del genoma completo. Establecer una causa etiológica es un componente crítico en la evaluación clínica de los pacientes con pérdida auditiva congénita, ya que puede ayudar a determinar las estrategias de manejo y rehabilitación, como el uso de auxiliares auditivos o implantes cocleares, proporcionar información sobre la progresión de la enfermedad y dar asesoramiento genético en esta población.

Displasia ectodérmica hipohidrótica ligada al cromosoma X de novo por variante recurrente en un paciente mexicano / X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient

Resumen Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

Abstract Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.

X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient.

Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.

Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

Niemann-Pick disease A or B in four pediatric patients and SMPD1 mutation carrier frequency in the Mexican population.

INTRODUCTION AND OBJECTIVES: Niemann-Pick disease type A (NPD-A) and B (NPD-B) are lysosomal storage diseases with a birth prevalence of 0.4-0.6/100,000. They are caused by a deficiency in acid sphingomyelinase, an enzyme encoded by SMPD1. We analyzed the phenotype and genotype of four unrelated Mexican patients, one with NPD-A and three with NPD-B. PATIENTS AND METHODS: Four female patients between 1 and 7 years of age were diagnosed with NPD-A or NPD-B by hepatosplenomegaly, among other clinical characteristics, and by determining the level of acid sphingomyelinase enzymatic activity and sequencing of the SMPD1 gene. Additionally, a 775bp amplicon of SMPD1 (from 11:6393835_6394609, including exons 5 and 6) was analyzed by capillary sequencing in a control group of 50 unrelated healthy Mexican Mestizos. RESULTS: An infrequent variant (c.1343A>G p.Tyr448Cys) was observed in two patients. One is the first NPD-A homozygous patient reported with this variant and the other a compound heterozygous NPD-B patient with the c.1829_1831delGCC p.Arg610del variant. Another compound heterozygous patient had the c.1547A>G p.His516Arg variant (not previously described in affected individuals) along with the c.1805G>A p.Arg602His variant. A new c.1263+8C>T pathogenic variant was encountered in a homozygous state in a NPD-B patient. Among the healthy control individuals there was a heterozygous carrier for the c.1550A>T (rs142787001) pathogenic variant, but none with the known pathogenic variants in the 11:6393835_6394609 region of SMPD1. CONCLUSIONS: The present study provides further NPD-A or B phenotype-genotype correlations. We detected a heterozygous carrier with a pathogenic variant in 1/50 healthy Mexican mestizos.

Out-of-pocket expenditures and care time for children with Down Syndrome: A single-hospital study in Mexico City.

AIM: To examine the burden of out-of-pocket household expenditures and time spent on care by families responsible for children with Down Syndrome (DS). METHODS: A cross-sectional analysis was performed after surveying families of children with DS. The children all received medical care at the Hospital Infantil de México Federico Gomez (HIMFG), a National Institute of Health. Data were collected on out-of-pocket household expenditures for the medical care of these children. The percentage of such expenditure was calculated in relation to available household expenditure (after subtracting the cost of food/housing), and the percentage of households with catastrophic expenditure. Finally, the time spent on the care of the child was assessed. RESULTS: The socioeconomic analysis showed that 67% of the households with children with DS who received medical care in the HIMFG were within the lower four deciles (I-IV) of expenses, indicating a limited ability to pay for medical services. Yearly out-of-pocket expenditures for a child with DS represented 27% of the available household expenditure, which is equivalent to $464 for the United States dollars (USD). On average, 33% of families with DS children had catastrophic expenses, and 46% of the families had to borrow money to pay for medical expenses. The percentage of catastrophic expenditure was greater for a household with children aged five or older compared with households with younger children. The regression analysis revealed that the age of the child is the most significant factor determining the time spent on care. CONCLUSIONS: Some Mexican families of children with DS incur substantial out-of-pocket expenditures, which constitute an economic burden for families of children who received medical care at the HIMFG.

Monosomía 9p24 secundaria a translocación (2; 9) en dos pacientes no relacionadas / Monosomy 9p24 in two non-related patients as result of a translocation (2; 9)

En pacientes con malformaciones congénitas y retraso del desarrollo psicomotor, deben descartarse cromosomopatías. Las más frecuentes son las translocaciones recíprocas balanceadas, presentes en 1:500 recién nacidos vivos. Por lo general, los portadores tienen fenotipo normal, aunque, ocasionalmente, presentan infertilidad, abortos o hijos con malformaciones. La translocación balanceada entre los cromosomas 2 y 9 puede originar descendencia con monosomías y trisomías de estos cromosomas. La monosomía del brazo corto del cromosoma 9 puede presentarse con trigonocefalia, dismorfias faciales, anomalías genitales y retraso del desarrollo psicomotor. En este trabajo, se revisaron las alteraciones de los cromosomas 2 y/o 9 en los cariotipos realizados en nuestra Institución en 2005-2014. Se presentan dos pacientes con monosomía 9p asociada a translocación (2;9). Las pacientes comparten datos de monosomía 9p24-pter; la correlación genotipo-fenotipo es compleja por el tamaño de los segmentos involucrados. Se resalta la importancia del diagnóstico cromosómico para el asesoramiento genético.

In patients with malformations and delayed psychomotor development it is important to discard chromosomopathies. Balanced reciprocal translocations are the most frequent chromosomopathies present in 1:500 live newborns. In general, carriers have normal phenotype, but they may have infertility, abortions or children with congenital malformations. The reciprocal translocation between chromosomes 2 and 9 can lead to offspring with monosomies and trisomies of these chromosomes. Short arm monosomy of chromosome 9 may present delayed psychomotor development, trigonocephaly, facial dysmorphia and genital abnormalities. We reviewed GTG karyotype records from our Institution to identify cases with chromosomes 2 and/or 9 alterations from 2005 to 2014. We describe two cases with monosomy 9p secondary to a translocation between chromosomes 2 and 9. The patients share features of monosomy 9p24-pter, however the genotype-phenotype correlation is complex due to the extension of the involved segments. We emphasize the importance of chromosomal diagnosis to offer genetic assessment.

A Novel c.91dupG JAG1 Gene Mutation Is Associated with Early Onset and Severe Alagille Syndrome.

Alagille syndrome (MIM 118450) is an autosomal dominant disorder characterized by paucity of intrahepatic bile ducts, chronic cholestasis, pulmonary stenosis, butterfly-like vertebrae, posterior embryotoxon, and dysmorphic facial features. Most cases are caused by JAG1 gene mutations. We report the case of a 2-year-old Mexican mestizo patient with Alagille syndrome, having exhibited jaundice and cholestatic syndrome as of three weeks of age. Sequencing analysis of the JAG1 gene revealed the novel heterozygous mutation c.91dupG that originates a truncated protein and therefore a possibly diminished activation of the Notch signaling pathway. The latter may explain the severe phenotype of the patient. Since the mutation was not identified in the parents, it was considered a de novo event, highlighting the importance of molecular diagnosis and genetic counseling. In conclusion, this report widens the spectrum of JAG1 gene mutations associated with Alagille syndrome.

Monosomy 9p24 in two non-related patients as result of a translocation (2;9). / Monosomía 9p24 secundaria a translocación (2;9) en dos pacientes no relacionadas.

In patients with malformations and delayed psychomotor development it is important to discard chromosomopathies. Balanced reciprocal translocations are the most frequent chromosomopathies present in 1:500 live newborns. In general, carriers have normal phenotype, but they may have infertility, abortions or children with congenital malformations. The reciprocal translocation between chromosomes 2 and 9 can lead to offspring with monosomies and trisomies of these chromosomes. Short arm monosomy of chromosome 9 may present delayed psychomotor development, trigonocephaly, facial dysmorphia and genital abnormalities. We reviewed GTG karyotype records from our Institution to identify cases with chromosomes 2 and/or 9 alterations from 2005 to 2014. We describe two cases with monosomy 9p secondary to a translocation between chromosomes 2 and 9. The patients share features of monosomy 9p24-pter, however the genotypephenotype correlation is complex due to the extension of the involved segments. We emphasize the importance of chromosomal diagnosis to offer genetic assessment.

En pacientes con malformaciones congénitas y retraso del desarrollo psicomotor, deben descartarse cromosomopatías. Las más frecuentes son las translocaciones recíprocas balanceadas, presentes en 1:500 recién nacidos vivos. Por lo general, los portadores tienen fenotipo normal, aunque, ocasionalmente, presentan infertilidad, abortos o hijos con malformaciones. La translocación balanceada entre los cromosomas 2 y 9 puede originar descendencia con monosomías y trisomías de estos cromosomas. La monosomía del brazo corto del cromosoma 9 puede presentarse con trigonocefalia, dismorfias faciales, anomalías genitales y retraso del desarrollo psicomotor. En este trabajo, se revisaron las alteraciones de los cromosomas 2 y/o 9 en los cariotipos realizados en nuestra Institución en 2005-2014. Se presentan dos pacientes con monosomía 9p asociada a translocación (2;9). Las pacientes comparten datos de monosomía 9p24-pter; la correlación genotipo-fenotipo es compleja por el tamaño de los segmentos involucrados. Se resalta la importancia del diagnóstico cromosómico para el asesoramiento genético.

Síndrome de Pallister-Killian en una paciente mestiza mexicana: Reporte de caso / Paüister-KiUian syndrome in a Mexican mestizo patient: Case report

El síndrome de Pallister-Killian es una entidad poco frecuente causada por tetrasomía 12p en mosaico. Presenta facies tosca, alopecia frontotemporal, frente prominente, fisuras palpebrales oblicuas ascendentes, hipertelorismo ocular, ptosis palpebral, estrabismo, epicanto, puente nasal ancho, nariz corta, narinas antevertidas, filtrum largo, labio superior delgado e inferior prominente, pabellones auriculares con lóbulos gruesos y protruidos, cuello corto, pezones supernumerarios, manos anchas, braquidactilia, alteraciones en la pigmentación de la piel, cardiopatía congénita, discapacidad intelectual y crisis convulsivas. Su diagnóstico es complejo, ya que, en sangre periférica, el cariotipo suele ser normal. Se presenta el caso de una paciente mestiza mexicana de 4 años de edad con retraso en el desarrollo psicomotor y características fenotípicas que correspondieron a síndrome de Pallister-Killian. El cariotipo en fibroblastos de la biopsia de piel demostró mos47,XX,i(12)(p10)--#91;85--#93;/46,XX--#91;21--#93;. Un equipo multidisciplinario realiza el seguimiento con controles regulares por los departamentos de Neurología, Pediatría General y Genética Médica.

Pallister-Killian syndrome is caused by a tetrasomy 12p mosaicism and is characterized by facial dysmorphism, pigmentary skin anomalies, congenital heart defects, diaphragmatic hernia, epilepsy and mental retardation. The diagnosis is complex as the cytogenetic analysis in blood is usually normal, requiring karyotyping in other tissues, therefore the clinical suspicion is critical to guide the diagnostic tests and the patient requires an interdisciplinary clinical evaluation regarding the several manifestation of the syndrome. W e present the case of a Mexican mestizo female patient of 4 years of age referred by psychomotor delay and cleft palate; the clinical multidisciplinary evaluation demonstrated characteristics corresponding to the Pallister-Killian syndrome. The GTG banding karyotype analysis was normal, the skin fibroblast was mos47,XX,i(12)(p10)--#91;85--#93;/46,XX--#91;21--#93;. This case is an example of the importance of the clinical evaluation in order to establish a diagnosis that is a challenge for the clinical multidisciplinary team to offer medical management and genetic counseling.

[Pallister-Killian syndrome in a Mexican mestizo patient. Case report]. / Síndrome de Pallister-Killian en una paciente mestiza mexicana. Reporte de caso.

Pallister-Killian syndrome is caused by a tetrasomy 12p mosaicism and is characterized by facial dysmorphism, pigmentary skin anomalies, congenital heart defects, diaphragmatic hernia, epilepsy and mental retardation. The diagnosis is complex as the cytogenetic analysis in blood is usually normal, requiring karyotyping in other tissues, therefore the clinical suspicion is critical to guide the diagnostic tests and the patient requires an interdisciplinary clinical evaluation regarding the several manifestation of the syndrome. W e present the case of a Mexican mestizo female patient of 4 years of age referred by psychomotor delay and cleft palate; the clinical multidisciplinary evaluation demonstrated characteristics corresponding to the Pallister-Killian syndrome. The GTG banding karyotype analysis was normal, the skin fibroblast was mos47,XX,i(12)(p10)[85]/46,XX[21]. This case is an example of the importance of the clinical evaluation in order to establish a diagnosis that is a challenge for the clinical multidisciplinary team to offer medical management and genetic counseling.

El síndrome de Pallister-Killian es una entidad poco frecuente causada por tetrasomía 12p en mosaico. Presenta facies tosca, alopecia frontotemporal, frente prominente, fisuras palpebrales oblicuas ascendentes, hipertelorismo ocular, ptosis palpebral, estrabismo, epicanto, puente nasal ancho, nariz corta, narinas antevertidas, filtrum largo, labio superior delgado e inferior prominente, pabellones auriculares con lóbulos gruesos y protruidos, cuello corto, pezones supernumerarios, manos anchas, braquidactilia, alteraciones en la pigmentación de la piel, cardiopatía congénita, discapacidad intelectual y crisis convulsivas. Su diagnóstico es complejo, ya que, en sangre periférica, el cariotipo suele ser normal. Se presenta el caso de una paciente mestiza mexicana de 4 años de edad con retraso en el desarrollo psicomotor y características fenotípicas que correspondieron a síndrome de Pallister-Killian. El cariotipo en fibroblastos de la biopsia de piel demostró mos47,XX,i(12)(p10)[85]/46,XX[21]. Un equipo multidisciplinario realiza el seguimiento con controles regulares por los departamentos de Neurología, Pediatría General y Genética Médica.

Nance-Horan syndrome in females due to a balanced X;1 translocation that disrupts the NHS gene: Familial case report and review of the literature.

The Nance-Horan syndrome is an X-linked disorder characterized by congenital cataract, facial features, microcornea, microphthalmia, and dental anomalies; most of the cases are due to NHS gene mutations on Xp22.13. Heterozygous carrier females generally present less severe features, and up to 30% of the affected males have intellectual disability. We describe two patients, mother and daughter, manifesting Nance-Horan syndrome. The cytogenetic and molecular analyses demonstrated a 46,X,t(X;1)(p22.13;q22) karyotype in each of them. No copy-number genomic imbalances were detected by high-density microarray analysis. The mother had a preferential inactivation of the normal X chromosome; expression analysis did not detect any mRNA isoform of NHS. This is the first report of Nance-Horan syndrome due to a skewed X chromosome inactivation resulting from a balanced translocation t(X;1) that disrupts the NHS gene expression, with important implications for clinical presentation and genetic counseling.

Craniosynostosis, delayed closure of the fontanelle, anal, genitourinary, and skin abnormalities (CDAGS syndrome): first report in a Mexican patient and review of the literature.

INTRODUCTION: Craniosynostosis and clavicular hypoplasia, delayed closure of the fontanelle, cranial defects, anal and genitourinary abnormalities, and skin (CDAGS), is an infrequent autosomal recessive entity with only 10 cases reported; no associated gene has been identified so far. CASE REPORT: The proband is a 2-year-old Mexican female with brachycephaly, cleft palate, anal malformation with rectovestibular fistula, and clinodactyly of the third toe overlapping the second. At 4 months of age, she developed a disseminated dermatosis with erythematous scaly nummular plaques, elevated keratotic sharp borders with thin to broad flaking, hematic crusts, and keratotic surface in others. The lesions were slightly pruritic and began at the lower limbs with posterior dissemination to the upper limbs, head, and trunk; palms and soles were unaffected. A skin biopsy showed hyperkeratosis, parakeratosis, acanthosis, and perivascular inflammatory infiltration in the upper reticular dermis among other alterations. She also presented mild bilateral neurosensory hypoacusia and enamel dysplasia. Her karyotype was normal. Treatment with topical hydrating creams partially improved the skin lesions at their center, while the sharply keratotic borders remained, giving a clinical resemblance to porokeratosis. DISCUSSION: The patient suffers from CDAGS syndrome but has normal development, and feet abnormality was described in only one other patient. The treatment with topical hydrating creams improved the skin lesions at their center, while porokeratotic characteristics persisted. CDAGS remains a diagnostic challenge; a comparison with previously reported cases is discussed. The timely detection of the syndrome will allow early treatment that may improve the condition of the patients.

Macroglosia congénita: características clínicas y estrategias de tratamiento en la edad pediátrica / Congenital macroglossia: clinical features and therapeutic strategies in paediatric patients

Resumen: La macroglosia congénita es una condición que se caracteriza por una lengua que en posición de reposo protruye más allá del borde alveolar; se ha clasificado en dos categorías: verdadera, que puede ser congénita o adquirida, y relativa. Debido a la asociación de esta alteración con múltiples causas, su incidencia es variable. Es más frecuente que la macroglosia se asocie con el síndrome de Beckwith-Wiedemann, con las mucopolisacaridosis y con la enfermedad de Pompe, y con menor frecuencia a linfangioma, hemangioma o hipertrofia muscular aislada. La macroglosia se caracteriza por una lengua alargada, engrosada o ancha, protruida crónicamente en reposo, con presencia o no de fisuras y úlceras, alteraciones del lenguaje, dificultad para la alimentación y deglución, sialorrea e infecciones recurrentes de la vía respiratoria superior u obstrucción de la misma. Su valoración en niños debe iniciarse con una historia clínica y exploración física completas y con la elaboración de un árbol genealógico de al menos tres generaciones, además de investigar la presencia o no de una entidad sindrómica. Se han propuesto más de 20 técnicas quirúrgicas para resolver la macroglosia congénita; sin embargo, a la fecha no existe consenso para la aplicación de una técnica en particular para reducir su tamaño. En esta revisión se pretende destacar los aspectos clínicos y quirúrgicos de la macroglosia, desde la perspectiva de pediatras no cirujanos y genetistas, dirigido a la comunidad de especialistas médicos que atiende a estos pacientes incluyendo a los cirujanos maxilofaciales que atienden a estos pacientes.

Abstract: Congenital macroglossia is a condition that consists in an enlarged tongue that in resting position protrudes beyond the alveolar ridge. It has been classified in two categories: true macroglossia, which occurs in congenital or acquired forms, and relative macroglossia. As this alteration may be due to different causes, its incidence is not known. It is more frequently associated to Beckwith-Wiedemann syndrome, to mucopolysaccharidosis diseases and to Pompe's disease, and it has been less frequently associated to lymphangioma, hemangioma or isolated muscular hypertrophy. Macroglossia is characterized by an enlarged and thick tongue that may have fissures and ulcers, may cause language alterations, difficulties for feeding and swallowing, sialorrhea and recurrent infections of the upper airway or even its obstruction. Its clinical evaluation must include a complete clinical chart with careful physical exploration and a pedigree of that may identify the presence or absence of a hereditary associated syndrome. Macroglossia management is complex. More than twenty different surgical options to reduce the tongue size have been proposed, however, so far there is not a general agreement in this respect. The objective of this work is to review clinical and surgical aspects related to macroglossia from the point of view of non-surgical pediatricians and genetists, addressed to the different medical specialists, including the maxillofacial surgeons involved in the management of these patients.

[Congenital macroglossia: clinical features and therapeutic strategies in paediatric patients]. / Macroglosia congénita: características clínicas y estrategias de tratamiento en la edad pediátrica.

Congenital macroglossia is a condition that consists in an enlarged tongue that in resting position protrudes beyond the alveolar ridge. It has been classified in two categories: true macroglossia, which occurs in congenital or acquired forms, and relative macroglossia. As this alteration may be due to different causes, its incidence is not known. It is more frequently associated to Beckwith-Wiedemann syndrome, to mucopolysaccharidosis diseases and to Pompe's disease, and it has been less frequently associated to lymphangioma, hemangioma or isolated muscular hypertrophy. Macroglossia is characterized by an enlarged and thick tongue that may have fissures and ulcers, may cause language alterations, difficulties for feeding and swallowing, sialorrhea and recurrent infections of the upper airway or even its obstruction. Its clinical evaluation must include a complete clinical chart with careful physical exploration and a pedigree of that may identify the presence or absence of a hereditary associated syndrome. Macroglossia management is complex. More than twenty different surgical options to reduce the tongue size have been proposed, however, so far there is not a general agreement in this respect. The objective of this work is to review clinical and surgical aspects related to macroglossia from the point of view of non-surgical pediatricians and genetists, addressed to the different medical specialists, including the maxillofacial surgeons involved in the management of these patients.

Velocardiofacial syndrome in Mexican patients: Unusually high prevalence of congenital heart disease.

INTRODUCTION: Velocardiofacial syndrome (VCFS) is the most common microdeletion syndrome with an incidence of 1:4000 live births. Its phenotype is highly variable with facial, velopharyngeal, cardiac, endocrine, immunologic and psychiatric abnormalities. It is caused by a microdeletion in chromosome 22q11.2. OBJECTIVES: We present 7 years of experience evaluating patients with VCFS regarding their main clinical characteristics. MATERIAL AND METHODS: The patients included were multidisciplinary evaluated and had a positive FISH analysis for del22q11.2. RESULTS: A total of 62 patients were assessed, a 34 female/28 male ratio was observed with ages ranging from 9 days to 16 years, all but one patient had typical facial features. A diagnosis of congenital heart disease was established in 97% of the patients; other clinical characteristics were identified with different percentages such as cleft palate, and hypocalcaemia. Three cases had a familial presentation. DISCUSSION: While the clinical findings of this study were in general terms in keeping with the literature, it is interesting the unexpectedly high percentage of congenital heart disease identified in Mexican children with VCFS that also was the main cause for clinical referral.

Cytogenetic profile in 1,921 cases of trisomy 21 syndrome.

BACKGROUND AND AIMS: Trisomy 21 is the most frequent genetic cause of intellectual disability. It is caused by different cytogenetic aberrations: free trisomy, Robertsonian translocations, mosaicism, duplication of the critical region and other structural rearrangements of chromosome 21. The aim of the study was to identify in Mexican trisomy 21 patients who attended Hospital Infantil de México Federico Gómez from 1992-2011 the type and frequency of the cytogenetic aberration and to evaluate the effect of maternal age. METHODS: A retrospective analysis of epidemiological data and karyotype reports were carried out; type and frequency of the cytogenetic variants were determined. RESULTS: We identified 2,018 cases referred with a clinical diagnosis of trisomy 21. In 1,921 analyses (95.2%) a cytogenetic variant of trisomy 21 was identified: free trisomy 21 in 1,787 cases (93.02%), four cases (0.21%) had an additional non-contributory aberration; Robertsonian translocations in 92 cases (4.79%); mosaicism in 31 cases (1.61%) and seven cases (0.36%) had other chromosomal abnormalities, five (0.26%) had other contributory structural rearrangements and two corresponded to double aneuploidies (0.10%). Gender distribution was 1,048 (54.56%) males and 873 (45.44%) females. A maternal age effect was observed in patients with free trisomy 21 with mothers >36 years of age. CONCLUSION: The present work reports the experience of a Mexican referral center regarding the karyotype diagnosis of patients with trisomy 21 and is one of the most extensive studies published so far. Percentages of the cytogenetic abnormalities present in our population reflect the ones previously reported for these cytogenetic alterations worldwide.

Brachmann-Cornelia de Lange syndrome with a papilloma of the choroid plexus: analyses of molecular genetic characteristics of the patient and the tumor. A single-case study.

PURPOSE: A 10-month-old girl with a Brachmann-Cornelia de Lange syndrome and a choroid plexus papilloma of the brain was studied at the Hospital Infantil de México Federico Gómez (HIMFG) in Mexico City. METHODS AND RESULTS: Presumptive papilloma of the third ventricle was evidenced on CT and MR images and removed. Pathological analysis confirmed its origin. A posterior radiosurgery was required due to a tumor relapse. Karyotypes (GTG bands) of the patient and her parents undertaken at HIMFG were normal. Array comparative genomic hybridization (array CGH) analyses of blood DNA of the patient and her parents carried out at BlueGnome's Laboratory in Cambridge, UK, set in evidence amplification of genes SPNS2, GGT6, SMTNL2, PELP1, MYBBP1A, and ALOX15 in chromosome 17p of the patient. Since MYBBP1A is a proto-oncogene and ALOX15 participates in the development of cancer and metastases of tumors, further fluorescent in situ hybridization (FISH) analyses of these two genes were implemented at HIMFG. Amplification of the two genes was found in the tumor of the case under study but not in an unrelated papilloma of the choroid plexus. DISCUSSION: Further analyses of the association of choroid plexus papillomas with disorders of psycho-neural development and its relationship to molecular genetic modifications at chromosome 17p are now under way at HIMFG.