Megalencephalic leukoencephalopathy with subcortical cysts: the importance of early diagnosis.

BACKGROUND: Megalencephalic leukoencephalopathy with subcortical cysts is a rare type of leukodystrophy associated with mutations in the MLC1 and GlialCAM genes. The classic form is characterized by macrocephaly, early or delayed normal neurodevelopment followed by a period of slow motor skill loss, with cerebellar ataxia and spasticity; some patients develop movement disorders and seizures. Magnetic resonance imaging shows widespread diffuse white matter involvement with edema and subcortical cysts. CASE REPORT: We describe the case of two sisters aged 6 and 10 years, consanguineous parents, with a history of psychomotor delay and macrocephaly. The older sister presented with seizures at the age of 4 years and spasticity without loss of gait; the younger sister had a similar clinical picture. Magnetic resonance imaging showed diffuse alteration of the white matter and subcortical cysts in the temporal lobes. Electroencephalogram detected focal epileptiform activity. Seizure control was achieved upon initiation of carbamazepine treatment. By sequencing, a homozygous variant of the MLC1 gene was found in exon 3: c.255T>G (p.Cys85Trp). CONCLUSIONS: Leukodystrophies are rare diseases that represent a diagnostic challenge. Clinical, radiological, and molecular findings allow diagnostic certainty, the appropriate direction of interventions, and adjustment to the prognosis of each entity. The c.255T>G mutation was previously described in a South American patients, suggesting that it is a specific variant to Latin populations.

INTRODUCCIÓN: La leucoencefalopatía megalencefálica con quistes subcorticales es una leucodistrofia poco frecuente, asociada con mutaciones en los genes MLC1 y GlialCAM. La forma clásica se caracteriza por macrocefalia, neurodesarrollo temprano normal o con retraso seguido por un periodo de pérdida lenta de habilidades motoras, con ataxia cerebelosa y espasticidad; algunos pacientes desarrollan trastornos del movimiento y crisis convulsivas. La resonancia magnética muestra afección difusa generalizada de la sustancia blanca con edema y quistes subcorticales. CASO CLÍNICO: Se presenta el caso de dos hermanas de 6 y 10 años con historia de retraso psicomotor y macrocefalia, hijas de padres consanguíneos. La mayor inició con crisis convulsivas a los 4 años y espasticidad sin pérdida de la marcha autónoma; la menor presentó un cuadro clínico similar. La resonancia magnética mostró una alteración difusa de la sustancia blanca y quistes subcorticales en los lóbulos temporales. El electroencefalograma detectó actividad epileptiforme focal. Se logró el control de las crisis convulsivas al iniciar el tratamiento con carbamazepina. Por secuenciación, se encontró una variante homocigota del gen MLC1 en el exón 3: c.255T>G (p.Cys85Trp). CONCLUSIONES: Las leucodistrofias son enfermedades raras que representan un desafío para su diagnóstico. Los hallazgos clínicos, radiológicos y moleculares permiten la certeza del diagnóstico, la dirección adecuada de las intervenciones y el ajuste al pronóstico de cada una. La mutación c.255T>G fue descrita previamente en pacientes sudamericanos, lo que sugiere que podría tratarse de una variante específica de poblaciones latinas.

Asociación entre la mutación homocigota c.318A>T en el exón 2 del gen EIF2B5 y la forma infantil de la leucoencefalopatía con sustancia blanca evanescente / Association between homozygous c.318A>GT mutation in exon 2 of the EIF2B5 gene and the infantile form of vanishing white matter leukoencephalopathy

Resumen: Introducción: La leucoencefalopatía con sustancia blanca evanescente es una de las leucodistrofias más frecuentes. Generalmente inicia en la infancia y presenta un patrón de herencia autosómica recesiva. El 90% de los casos manifiesta mutaciones en uno de los genes que codifican para las cinco subunidades del factor de iniciación eucariótica 2 (EIF2B5). El diagnóstico se realiza por las manifestaciones clínicas, hallazgos en la resonancia magnética cerebral y estudios moleculares confirmatorios. Caso clínico: Paciente masculino de 13 meses con neurodesarrollo previo normal. Antecedente de internamiento por vómito, hipertermia, irritabilidad y rechazo a la vía oral de 15 días de evolución. Ante la exploración presentó perímetro cefálico y pares craneales normales. Se encontró hipotónico, con reflejos incrementados, sin datos meníngeos ni de cráneo hipertensivo. La tomografía de cráneo mostró hipodensidad generalizada de la sustancia blanca. Egresó sin recuperar deambulación. A los 15 días presentó somnolencia y crisis convulsivas focales después de traumatismo craneoencefálico. En la resonancia magnética se observó hipointensidad generalizada de sustancia blanca. Ante la sospecha de leucoencefalopatía con sustancia blanca evanescente, se solicitó la secuenciación del gen EIF2B5, que reportó mutación homocigota c.318A>T en el exón 2. El paciente requirió múltiples hospitalizaciones por hipertermia y descontrol de crisis convulsivas. Posteriormente mostró deterioro cognitivo, motor y pérdida de la agudeza visual. Falleció a los 6 años por neumonía severa. Conclusiones: Este caso contribuye a conocer el espectro de mutaciones que se presenta en pacientes mexicanos y permite ampliar el fenotipo asociado con esta mutación.

Abstract: Background: Vanishing white matter disease is one of the most frequent leukodystrophies in childhood with an autosomal recessive inheritance. A mutation in one of the genes encoding the five subunits of the eukaryotic initiation factor 2 (EIF2B5) is present in 90% of the cases. The diagnosis can be accomplished by the clinical and neuroradiological findings and molecular tests. Case report: We describe a thirteen-month-old male with previous normal neurodevelopment, who was hospitalized for vomiting, hyperthermia and irritability. On examination, cephalic perimeter and cranial pairs were normal. Hypotonia, increased muscle stretching reflexes, generalized white matter hypodensity on cranial tomography were found. Fifteen days after discharge, he suffered minor head trauma presenting drowsiness and focal seizures. Magnetic resonance showed generalized hypointensity of white matter. Vanishing white matter disease was suspected, and confirmed by sequencing of the EIF2B5 gene, revealing a homozygous c.318A> T mutation in exon 2. Subsequently, visual acuity was lost and cognitive and motor deterioration was evident. The patient died at six years of age due to severe pneumonia. Conclusions: This case contributes to the knowledge of the mutational spectrum present in Mexican patients and allows to extend the phenotype associated to this mutation.

[Association between homozygous c.318A>GT mutation in exon 2 of the EIF2B5 gene and the infantile form of vanishing white matter leukoencephalopathy]. / Asociación entre la mutación homocigota c.318A>T en el exón 2 del gen EIF2B5 y la forma infantil de la leucoencefalopatía con sustancia blanca evanescente.

BACKGROUND: Vanishing white matter disease is one of the most frequent leukodystrophies in childhood with an autosomal recessive inheritance. A mutation in one of the genes encoding the five subunits of the eukaryotic initiation factor 2 (EIF2B5) is present in 90% of the cases. The diagnosis can be accomplished by the clinical and neuroradiological findings and molecular tests. CASE REPORT: We describe a thirteen-month-old male with previous normal neurodevelopment, who was hospitalized for vomiting, hyperthermia and irritability. On examination, cephalic perimeter and cranial pairs were normal. Hypotonia, increased muscle stretching reflexes, generalized white matter hypodensity on cranial tomography were found. Fifteen days after discharge, he suffered minor head trauma presenting drowsiness and focal seizures. Magnetic resonance showed generalized hypointensity of white matter. Vanishing white matter disease was suspected, and confirmed by sequencing of the EIF2B5 gene, revealing a homozygous c.318A> T mutation in exon 2. Subsequently, visual acuity was lost and cognitive and motor deterioration was evident. The patient died at six years of age due to severe pneumonia. CONCLUSIONS: This case contributes to the knowledge of the mutational spectrum present in Mexican patients and allows to extend the phenotype associated to this mutation.

Lethal Keratitis, Ichthyosis, and Deafness Syndrome Due to the A88V Connexin 26 Mutation.

Keratitis-ichthyosis-deafness syndrome is a well-characterized disease that has been related to mutations in the GJB6 gene. Clinical features such as erythrokeratoderma, palmoplantar keratoderma, alopecia, and progressive vascularizing keratitis, among others, are well known in this entity. In this report we describe a newborn female patient diagnosed with keratitis-ichthyosis-deafness syndrome with a lethal outcome due to sepsis. The patient harbored the mutation A88V that has been previously reported in lethal cases.

Presentación atípica de la enfermedad de Alexander infantil sin macrocefalia / An atypical presentation of Infantile Alexander disease lacking macrocephaly

Resumen: Introducción: La enfermedad de Alexander consiste en una forma de leucodistrofia poco frecuente que afecta principalmente a los astrocitos; tiene un patrón de herencia autosómica recesiva y es causada por mutaciones en el gen GFAP, localizado en el cromosoma 17q21. Puede presentarse a cualquier edad y la forma infantil se caracteriza por macrocefalia, crisis convulsivas, retraso motor y cognitivo grave y espasticidad o ataxia progresivas. Caso clínico: Paciente de sexo femenino de 8 meses evaluada por retraso psicomotor y crisis convulsivas motoras focales no provocadas. En la exploración física, con perímetro cefálico normal, respuesta motora incrementada ante estímulos táctiles y al ruido, signos piramidales y ausencia de visceromegalias. Se observó hipodensidad generalizada de la sustancia blanca en la resonancia magnética y punción lumbar con hiperproteinorraquia. Se descartó enfermedad de Krabbe mediante ensayo enzimático y secuenciación del gen GALC. En la reevaluación del caso, las alteraciones en la neuroimagen hicieron sospechar de enfermedad de Alexander, y la secuenciación del gen GFAP reportó una mutación en el exón 4 c.716G > A, lo que ocasionó un cambio de arginina por histidina en la posición 239 de la proteína (p.Arg239His). Conclusiones: Los signos radiológicos en la resonancia fueron determinantes para el diagnóstico, que posteriormente se confirmó con estudio molecular. Es importante considerar que ciertas mutaciones no se asocian con macrocefalia, lo cual puede ocasionar retraso en el diagnóstico.

Abstract: Background: Alexander disease is a rare form of leukodystrophy that involves mainly astrocytes; it is inherited in an autosomal recessive manner and occurs by mutations in the GFAP gene, located on chromosome 17q21. It can occur at any age and its infantile form is characterized by macrocephaly, seizures, severe motor and cognitive delay, and progressive spasticity or ataxia. Case report: An 8-month-old female was evaluated with a history of neurodevelopmental delay and unprovoked focal motor seizures. Physical examination showed normal head circumference, increased motor responses to tactile and noise stimuli, pyramidal signs and no visceromegalies. Widespread hypodense white matter was found on magnetic resonance and lumbar puncture showed hyperproteinorrachia. Krabbe disease was ruled out by enzymatic assay and gene sequencing of GALC. In the reassessment of the case, abnormalities in neuroimaging lead to suspicion of Alexander disease, and GFAP gene sequencing reported a pathogenic mutation in exon 4 c.716G > A, which caused a change of arginine to histidine at position 239 of the protein (p.Arg239His). Conclusions: The radiographic signs observed in the resonance were decisive for the diagnosis, later confirmed by molecular study. It is important to consider that certain mutations are not associated with macrocephaly, which may cause delay in diagnosis.

[An atypical presentation of Infantile Alexander disease lacking macrocephaly]. / Presentación atípica de la enfermedad de Alexander infantil sin macrocefalia.

BACKGROUND: Alexander disease is a rare form of leukodystrophy that involves mainly astrocytes; it is inherited in an autosomal recessive manner and occurs by mutations in the GFAP gene, located on chromosome 17q21. It can occur at any age and its infantile form is characterized by macrocephaly, seizures, severe motor and cognitive delay, and progressive spasticity or ataxia. CASE REPORT: An 8-month-old female was evaluated with a history of neurodevelopmental delay and unprovoked focal motor seizures. Physical examination showed normal head circumference, increased motor responses to tactile and noise stimuli, pyramidal signs and no visceromegalies. Widespread hypodense white matter was found on magnetic resonance and lumbar puncture showed hyperproteinorrachia. Krabbe disease was ruled out by enzymatic assay and gene sequencing of GALC. In the reassessment of the case, abnormalities in neuroimaging lead to suspicion of Alexander disease, and GFAP gene sequencing reported a pathogenic mutation in exon 4 c.716G>A, which caused a change of arginine to histidine at position 239 of the protein (p.Arg239His). CONCLUSIONS: The radiographic signs observed in the resonance were decisive for the diagnosis, later confirmed by molecular study. It is important to consider that certain mutations are not associated with macrocephaly, which may cause delay in diagnosis.

Frequency of SMN1 deletion carriers in a Mestizo population of central and northeastern Mexico: A pilot study.

Individuals who suffer from spinal muscular atrophy (SMA) exhibit progressive muscle weakness that frequently results in mortality in the most severe forms of the disease. In 98% of cases, there is a homozygous deletion of the survival of motor neuron 1 (SMN1) gene, and both parents carry the same heterozygous genetic abnormality in the majority of cases. Various population studies have been conducted to estimate the frequency of carriers and thereby identify the communities or countries in which children are at a high risk of being affected by SMA. However, the prevalence of SMA in Mexican populations has not yet been established. In the present pilot study, the frequency of the heterozygous deletion of the SMN1 gene was determined in two groups from northeastern (n=287) and central (n=133) Mexican Mestizo populations and compared with other ethnic populations. Amplification refractory mutation system polymerase chain reaction analysis yielded a disease carrier frequency of 11/420 (2.62%) healthy individuals, comprising 9/287 (3.14%) northeastern and 2/133 (1.5%) central Mexican individuals. In summary, no significant differences were identified between the northeastern and central populations of Mexico and other ethnic populations, with the exception of the general worldwide Hispanic population, which exhibited the lowest carrier frequency of 8/1,030. The results of the present study may be used to improve the evaluation procedure, and appear to justify further studies involving larger sample populations.

A novel interstitial deletion of 2q22.3 q23.3 in a patient with dysmorphic features, epilepsy, aganglionosis, pure red cell aplasia, and skeletal malformations.

Many chromosomal deletions encompassing the 2q23.1 region have been described ranging from small deletions of 38 kb up to >19 Mb. Most phenotypic features of the 2q23.1 deletion syndrome are due to a MBD5 gene loss independent of the size of the deletion. Here, we describe a male patient harboring a novel interstitial deletion encompassing the 2q22.3 q23.3 chromosomal region. Array-CGH revealed a 7.1 Mb deletion causing haploinsufficiency of several genes including MBD5, ACVR2, KIF5C, and EPC2. This patient presents with additional findings to those already described in individuals who have deletions of MBD5 including toes absence of halluces, pure red cell aplasia, and intestinal aganglionosis. Interestingly, in the deleted region there are previously identified regulatory sequences which are located upstream to ZEB2, which is associated with Hirschsprung disease (HSCR). Several genes have been associated with pure red cell aplasia, but to our knowledge, this is the first time that 2q deletion is associated with this phenotype. These additional findings should be added to the list of manifestations associated with 2q deletion, and provide support for the hypothesis that this individual has a true contiguous gene deletion syndrome.

Hallazgos clínicos y moleculares en una paciente con ataxia por deficiencia de vitamina E, homocigota para la mutación c.205-1G>C en el gen TTPA / Clinical and molecular findings in a patient with ataxia with vitamin E deficiency, homozygous for the c.205-1G>C mutation in the TTPA gene

Introducción. La ataxia por deficiencia de vitamina E es causada por mutaciones en el gen TTPA . Está caracterizada por ataxia, arreflexia, temblor cefálico, pérdida de la propiocepción, Babinsky, disdiadococinesia, retinitis pigmentosa y cardiomiopatía. Caso clínico. Se trató de una paciente del sexo femenino de 11 años, padres consanguíneos, valorada por dolor y parestesias en miembros inferiores, disartria y problemas para escribir y masticar. El examen físico mostró fuerza distal disminuida, hiperreflexia, Babinsky, disminución en la propiocepción, pie cavo bilateral, dismetría, disdiadococinesia y Romberg positivo. El estudio para ataxia de Friedreich resultó normal, aunque presentó bajos niveles de a-tocoferol y se identificó una mutación homocigota c.205-1G>C en el gen TTPA . Se inició tratamiento con vitamina E con lo que mostró mejoría. Conclusiones. Ante la presencia de manifestaciones parecidas a la ataxia de Friedreich se sugiere evaluar niveles plasmáticos de α-tocoferol y realizar estudios genéticos confirmatorios. El tratamiento con vitamina E disminuye los síntomas en los afectados y los presintomáticos no desarrollan manifestaciones del trastorno. Se han reportado pocos casos en Latinoamérica. En esta paciente se encontró una mutación en estado homocigoto fuera de las áreas de mayor prevalencia. Dichos hallazgos clínicos pueden indicar que la mutación c.205-1G>C se asocia con un cuadro severo.

Background. Ataxia with vitamin E deficiency is a disorder caused by mutations in the TTPA gene. Common symptoms include ataxia, areflexia, head titubation, loss of proprioception, Babinsky sign, dysdiadochokinesia, pigmentary retinopathy and cardiomyopathy. Case report. The patient was the first child of consanguineous parents. She presented at 10 years of age due to bilateral lower limb pain and numbness and difficulty in speech, writing and chewing. Physical examination showed dysarthria, diminished distal strength, hyperreflexia, positive Babinsky sign, decreased proprioception, pes cavus, dysmetria, dysdiadochokinesia and positive Romberg sign. Genetic screening for the Friedreich's ataxia gene resulted negative, α-tocopherol levels were low and TTPA gene sequentiation detected the homozygous mutation c.205-1G >C in intron 1. Treatment was initiated with vitamin E, showing improvement of symptoms. Conclusions. The presence of Friedreich's ataxia-like phenotype suggests the need to perform tests of plasma levels of α-tocopherol and the confirmatory genetic test. Treatment with vitamin E decreases symptoms in both affected and presymptomatic individuals. Few patients have been described in America, and our case showed a homozygous mutation outside of high-prevalence areas. Clinical findings of this patient and a previous case would indicate that the c.205-1G>C mutation is associated with severe symptoms.

The interstitial duplication 15q11.2-q13 syndrome includes autism, mild facial anomalies and a characteristic EEG signature.

Chromosomal copy number variants (CNV) are the most common genetic lesion found in autism. Many autism-associated CNVs are duplications of chromosome 15q. Although most cases of interstitial (int) dup(15) that present clinically are de novo and maternally derived or inherited, both pathogenic and unaffected paternal duplications of 15q have been identified. We performed a phenotype/genotype analysis of individuals with interstitial 15q duplications to broaden our understanding of the 15q syndrome and investigate the contribution of 15q duplication to increased autism risk. All subjects were recruited solely on the basis of interstitial duplication 15q11.2-q13 status. Comparative array genome hybridization was used to determine the duplication size and boundaries while the methylation status of the maternally methylated small nuclear ribonucleoprotein polypeptide N gene was used to determine the parent of origin of the duplication. We determined the duplication size and parental origin for 14 int dup(15) subjects: 10 maternal and 4 paternal cases. The majority of int dup(15) cases recruited were maternal in origin, most likely due to our finding that maternal duplication was coincident with autism spectrum disorder. The size of the duplication did not correlate with the severity of the phenotype as established by Autism Diagnostic Observation Scale calibrated severity score. We identified phenotypes not comprehensively described before in this cohort including mild facial dysmorphism, sleep problems and an unusual electroencephalogram variant. Our results are consistent with the hypothesis that the maternally expressed ubiquitin protein ligase E3A gene is primarily responsible for the autism phenotype in int dup(15) since all maternal cases tested presented on the autism spectrum.

A novel homozygous mutation at the GAA gene in Mexicans with early-onset Pompe disease.

Glycogen-storage disease type II, also named Pompe disease, is caused by the deficiency of the enzyme acid alpha-glucosidase, which originates lysosomal glycogen accumulation leading to progressive neuromuscular damage. Early-onset Pompe disease shows a debilitating and frequently fulminating course. To date, more than 300 mutations have been described; the majority of them are unique to each affected individual. Most early-onset phenotypes are associated with frameshift mutations leading to a truncated alpha-glucosidase protein with loss of function. Founder effects are responsible from many cases from few highprevalence world regions. Herein we described two apparently unrelated cases affected with classical early-onset Pompe disease, both pertaining to a small region from Central Mexico (the State of San Luis Potosí), the same novel homozygous frameshift mutation at gene GAA (c.1987delC) was demonstrated in both cases. This GAA gene deletion implies a change of glutamine to serine at codon 663, and a new reading frame that ends after 33 base pairs, which leads to the translation of a truncated protein. This report contributes to widen the knowledge on the effect of pathogenic mutations in Pompe disease. Here we postulate the existence of a founder effect.

Severe consequences of carbamazepine exposure in utero.

The 'foetal carbamazepine syndrome' is characterised by facial dysmorphism associated to cardiovascular, nervous system, urinary tract and skeletal anomalies. The authors present the case of a neonate born to a 33-year-old epileptic woman treated with long term carbamazepine (CMZ) therapy. Four of her pregnancies exposed to the drug showed bad outcomes. The actual pregnancy ended by caesarean section, a female was born showing facial dysmorphism, hypoplasic nails, xyphosis and myelomeningocele. After 7 days of birth, the infant developed severe neutropenia, moderate pulmonary hypertension, multiple organ failure and died. The karyotype was 46, XX. This case represents an example of the wide spectrum of the syndrome and contributes to describe the clinical profile of the 'foetal carbamazepine syndrome'. The delineation of the foetal carbamazepine syndrome's phenotype remains incomplete, since many of the clinical manifestations are shared with the effect of others anticonvulsants, therefore further studies are needed to determine the specific noxious effects of CMZ in utero.

[Expand newborn screening using tandem mass spectrometry: two years' experience in Nuevo León, Mexico]. / Tamiz metabólico neonatal por espectrometría de masas en tándem: dos años de experiencia en Nuevo León, México.

OBJECTIVE: To initiate a statewide expanded metabolic screening program in neonates with the purpose of identifying the most common inborn errors of metabolism. MATERIAL AND METHODS: From March 2002 through February 2004, a blood sample was obtained between 24 and 48 hours after delivery from every consecutive child born in public hospitals in Nuevo León. It was spotted on filter paper and analyzed by tandem mass spectrometry for expanded metabolic screening. RESULTS: A total of 42 264 samples were analyzed. Were obtained seven positive results, one for each disorder: homocystinuria, hyperphenylalaninemia, citrulinemia, transient tyrosinemia, 3-methylcrotonyl CoA carboxylase deficiency, 3-hydroxy-3-methylglutaryl CoA deficiency, and classic galactosemia. CONCLUSIONS: The estimated incidence of inborn errors of metabolism is 1:5 000, with a false positive rate of 0.22%. The program permitted the identification of metabolic disorders in the newborn, allowing an early intervention and prevention of life-threatening events and permanent neurological damage.

Tamiz metabólico neonatal por espectrometría de masas en tándem: dos años de experiencia en Nuevo León, México / Expand newborn screening using tandem mass spectrometry: two years' experience in Nuevo León, Mexico

OBJETIVO: Instituir un programa estatal de tamizaje neonatal ampliado para identificar errores innatos del metabolismo y determinar su prevalencia en la población de recién nacidos del estado de Nuevo León. MATERIAL Y MÉTODOS: Entre marzo de 2002 y febrero de 2004 se incluyeron neonatos consecutivos nacidos en hospitales públicos del estado. Se colectaron muestras de sangre en papel filtro entre las 24 y 48 horas de vida y se las sometió a tamiz metabólico mediante espectrometría de masas en tándem. RESULTADOS: Se analizaron 42 264 primeras muestras y se detectaron siete casos, uno de cada padecimiento: homocistinuria, fenilcetonuria, citrulinemia, tirosinemia/transitoria, deficiencia de 3-metilcrotonil-CoA carboxilasa, deficiencia de 3-hidroxi-3-metilglutaril-CoA liasa y galactosemia típica. CONCLUSIONES: La incidencia acumulada de defectos metabólicos en la población fue de 1:5 000 con 0.22 por ciento de casos falso-positivos. El programa permitió identificar y tratar con oportunidad los trastornos metabólicos al nacimiento con una efectiva prevención secundaria del retraso mental.

OBJECTIVE: To initiate a statewide expanded metabolic screening program in neonates with the purpose of identifying the most common inborn errors of metabolism. MATERIAL AND METHODS: From March 2002 through February 2004, a blood sample was obtained between 24 and 48 hours after delivery from every consecutive child born in public hospitals in Nuevo León. It was spotted on filter paper and analyzed by tandem mass spectrometry for expanded metabolic screening. RESULTS: A total of 42 264 samples were analyzed. Were obtained seven positive results, one for each disorder: homocystinuria, hyperphenylalaninemia, citrulinemia, transient tyrosinemia, 3-methylcrotonyl CoA carboxylase deficiency, 3-hydroxy-3-methylglutaryl CoA deficiency, and classic galactosemia. CONCLUSIONS: The estimated incidence of inborn errors of metabolism is 1:5 000, with a false positive rate of 0.22 percent. The program permitted the identification of metabolic disorders in the newborn, allowing an early intervention and prevention of life-threatening events and permanent neurological damage.

Patient follow-up is a major problem at genetics clinics.

Children with genetic diseases must be followed for long periods of time to seek new findings. Other patients require further check-ups and studies to be diagnosed. Some patients never return for medical care after the first consultation, which may have serious consequences. We reviewed 400 medical charts of patients with genetic disease to analyze overall attendance to the genetics clinic, investigate some of the causes of failure to seek medical advice, and determine the differences between those first seen as outpatients or as inpatients. The mean follow-up period was 8.3 months (range 0-79), and the average number of visits was 2.8 (range 1-16). Forty eight percent of the cases first seen as inpatients were evaluated only once and 14% twice; while 22 and 21% of the 300 cases first seen as outpatients attended once and twice, respectively (P = 0.0). Appointment keeping was apparently not affected by the presence or absence of diagnosis. Overall, 97 patients were discharged, 7 died, 55 continued on follow-up, 62 attended other hospital services-but not genetics-and 179 were completely lost to follow-up. Diagnosed patients were counseled more frequently than undiagnosed patients (62 vs. 5%); and 71% of the diagnosed patients first seen as outpatients but only 36% of undiagnosed cases first seen as inpatients were counseled, differences between these two groups were significant (P = 0.005). We conclude that keeping the patient with genetic disease on follow-up is a difficult task. New educational strategies must be planned to improve this worrisome situation.

DEB test for Fanconi anemia detection in patients with atypical phenotypes.

Pancytopenia, hyperpigmentation, small stature, congenital abnormalities, and predisposition to neoplasia characterize Fanconi anemia (FA). The clinical phenotype is extremely variable, therefore the diagnosis is frequently delayed until the pancytopenia appears, making diagnosis difficult on the basis of clinical manifestations alone. Hypersensitivity of FA cells to the clastogenic effect of diepoxybutane (DEB) provides a unique marker for the diagnosis before the beginning of hematological manifestations. Our aim in this study was to detect FA in children with atypical manifestations to define which conditions should be routinely included in the DEB test screening. We performed the chromosomal breakage test in 34 patients with probable FA and 83 patients with clinical conditions that could suggest FA, but are not usually screened by the DEB test: 20 patients with aplastic anemia, 20 patients with VACTERL association, 20 with radial ray abnormalities, 7 with tracheo-esophageal fistulae, 12 with anal atresia, and 4 with myelodysplastic syndrome. We found 18 DEB-positive patients: 12 were in the group of probable FA and 6 in the other groups. Among the last ones: three were included because of aplastic anemia, without any other sign of FA, however when re-examined, other anomalies were detected. The third patient had anal atresia, renal hypoplasia, pre-axial polydactyly, and normal blood cell counts and was diagnosed as having VACTERL association. The other two patients lacking physical or hematological signs were identified among the group of radial ray abnormalities. Thus, our results highlight the need to increase the number of abnormalities indicating need for a DEB test. Delay in the diagnosis of FA may have serious consequences for the patients and their family members.