RESUMEN
Microcephalic osteodysplastic primordial dwarfism type I (MOPDI) is a very rare and severe autosomal recessive disorder characterized by marked intrauterine growth retardation, skeletal dysplasia, microcephaly and brain malformations. MOPDI is caused by biallelic mutations in RNU4ATAC, a non-coding gene involved in U12-type splicing of 1% of the introns in the genome, which are recognized by their specific splicing consensus sequences. Here, we describe a unique observation of immunodeficiency in twin sisters with mild MOPDI, who harbor a novel n.108_126del mutation, encompassing part of the U4atac snRNA 3' stem-loop and Sm protein binding site, and the previously reported n.111G>A mutation. Interestingly, both twin sisters show mild B-cell anomalies, including low naive B-cell counts and increased memory B-cell and plasmablasts counts, suggesting partial and transitory blockage of B-cell maturation and/or excessive activation of naive B-cells. Hence, the localization of a mutation in stem II of U4atac snRNA, as observed in another RNU4ATAC-opathy with immunodeficiency, that is, Roifman syndrome (RFMN), is not required for the occurrence of an immune deficiency. Finally, we emphasize the importance of considering immunodeficiency in MOPDI management to reduce the risk of serious infectious episodes.
RESUMEN
NCKAP1/NAP1 regulates neuronal cytoskeletal dynamics and is essential for neuronal differentiation in the developing brain. Deleterious variants in NCKAP1 have been identified in individuals with autism spectrum disorder (ASD) and intellectual disability; however, its clinical significance remains unclear. To determine its significance, we assemble genotype and phenotype data for 21 affected individuals from 20 unrelated families with predicted deleterious variants in NCKAP1. This includes 16 individuals with de novo (n = 8), transmitted (n = 6), or inheritance unknown (n = 2) truncating variants, two individuals with structural variants, and three with potentially disruptive de novo missense variants. We report a de novo and ultra-rare deleterious variant burden of NCKAP1 in individuals with neurodevelopmental disorders which needs further replication. ASD or autistic features, language and motor delay, and variable expression of intellectual or learning disability are common clinical features. Among inherited cases, there is evidence of deleterious variants segregating with neuropsychiatric disorders. Based on available human brain transcriptomic data, we show that NCKAP1 is broadly and highly expressed in both prenatal and postnatal periods and demostrate enriched expression in excitatory neurons and radial glias but depleted expression in inhibitory neurons. Mouse in utero electroporation experiments reveal that Nckap1 loss of function promotes neuronal migration during early cortical development. Combined, these data support a role for disruptive NCKAP1 variants in neurodevelopmental delay/autism, possibly by interfering with neuronal migration early in cortical development.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Trastorno del Espectro Autista/genética , Discapacidad Intelectual/genética , Discapacidades para el Aprendizaje/genética , Mutación , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Adolescente , Animales , Trastorno del Espectro Autista/diagnóstico , Trastorno del Espectro Autista/patología , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Niño , Femenino , Expresión Génica , Genotipo , Células HEK293 , Humanos , Discapacidad Intelectual/diagnóstico , Discapacidad Intelectual/patología , Discapacidades para el Aprendizaje/diagnóstico , Discapacidades para el Aprendizaje/patología , Masculino , Ratones , Ratones Noqueados , Neuroglía/metabolismo , Neuroglía/patología , Neuronas/metabolismo , Neuronas/patología , Linaje , Fenotipo , Embarazo , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transcriptoma , Adulto JovenRESUMEN
Primary defects in lung branching morphogenesis, resulting in neonatal lethal pulmonary hypoplasias, are incompletely understood. To elucidate the pathogenetics of human lung development, we studied a unique collection of samples obtained from deceased individuals with clinically and histopathologically diagnosed interstitial neonatal lung disorders: acinar dysplasia (n = 14), congenital alveolar dysplasia (n = 2), and other lethal lung hypoplasias (n = 10). We identified rare heterozygous copy-number variant deletions or single-nucleotide variants (SNVs) involving TBX4 (n = 8 and n = 2, respectively) or FGF10 (n = 2 and n = 2, respectively) in 16/26 (61%) individuals. In addition to TBX4, the overlapping â¼2 Mb recurrent and nonrecurrent deletions at 17q23.1q23.2 identified in seven individuals with lung hypoplasia also remove a lung-specific enhancer region. Individuals with coding variants involving either TBX4 or FGF10 also harbored at least one non-coding SNV in the predicted lung-specific enhancer region, which was absent in 13 control individuals with the overlapping deletions but without any structural lung anomalies. The occurrence of rare coding variants involving TBX4 or FGF10 with the putative hypomorphic non-coding SNVs implies a complex compound inheritance of these pulmonary hypoplasias. Moreover, they support the importance of TBX4-FGF10-FGFR2 epithelial-mesenchymal signaling in human lung organogenesis and help to explain the histopathological continuum observed in these rare lethal developmental disorders of the lung.
Asunto(s)
Factor 10 de Crecimiento de Fibroblastos/genética , Enfermedades del Recién Nacido/genética , Enfermedades del Recién Nacido/mortalidad , Enfermedades Pulmonares/genética , Enfermedades Pulmonares/mortalidad , Transducción de Señal/genética , Proteínas de Dominio T Box/genética , Variaciones en el Número de Copia de ADN/genética , Femenino , Factor 10 de Crecimiento de Fibroblastos/metabolismo , Regulación de la Expresión Génica , Edad Gestacional , Humanos , Recién Nacido , Enfermedades del Recién Nacido/metabolismo , Enfermedades del Recién Nacido/patología , Pulmón/embriología , Pulmón/crecimiento & desarrollo , Enfermedades Pulmonares/metabolismo , Enfermedades Pulmonares/patología , Masculino , Herencia Materna , Organogénesis , Herencia Paterna , Linaje , Polimorfismo de Nucleótido Simple/genética , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/metabolismo , Proteínas de Dominio T Box/metabolismoRESUMEN
PURPOSE: Subependymal giant-cell astrocytomas (SEGAs) are low grade intraventricular tumors typically found in patients with tuberous sclerosis complex (TSC). The occurrence of SEGA in non TSC patients is very rare and from a genetic point of view these so-called solitary SEGA are thought to result either from somatic mutations in one of the TSC genes (TSC1 or TSC2) limited to the tumor, or be part of a "forme fruste" of TSC with somatic mosaicism. We report on three new cases of solitary SEGA with germline and somatic mutation analysis. METHODS: We retrospectively analyzed TSC genes in three patients with a solitary SEGA using next-generation sequencing technique. RESULTS: In the three patients, a somatic mutation of TSC1 or TSC2 was found only in the tumor cells: one patient had a TSC1 heterozygote mutation, involving the natural acceptor splicing site of intron 15 (c.1998-1G > A (p.?). Two patients had a TSC2 mutation located in the canonical splicing donor site of intron 5 (c.599 + 1G > A) in 70% of the alleles in one patient and in exon 9: c.949_955dup7 (p.V319DfxX21) in 25 of the alleles in the second patient. No other TSC mutations were found in patient's blood or tumor and those identified mutations were absent in blood DNA from parents and siblings. CONCLUSION: We therefore conclude that solitary SEGA can occur with a TSC1 or TSC2 mutation limited to the tumor in patients without TSC.
Asunto(s)
Astrocitoma , Astrocitoma/diagnóstico por imagen , Astrocitoma/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mutación , Estudios Retrospectivos , Tecnología , Proteína 1 del Complejo de la Esclerosis Tuberosa/genética , Proteína 2 del Complejo de la Esclerosis Tuberosa/genéticaRESUMEN
We report here on an 8-year-old girl and her mother, both displaying similar facial dysmorphism, speech delay, and mild to moderate intellectual disability. Array-CGH studies revealed the same interstitial 3q26.32 microdeletion encompassing a single coding gene, TBL1XR1, in both patients. The TBL1XR1 protein, which has four WD40 repeats, has been shown to bind the nuclear corepressor (NCOR) and histone deacetylase-3 complexes (HDAC3). TBL1XR1 mutations have recently been implicated in autism spectrum disorders, but our patients displayed no autistic behavior. Our findings suggest that TBL1XR1 haploinsufficiency can cause intellectual disability with a recognizable dysmorphism, without necessarily causing autistic behavior.
Asunto(s)
Deleción Cromosómica , Facies , Discapacidad Intelectual/genética , Proteínas Nucleares/genética , Receptores Citoplasmáticos y Nucleares/genética , Proteínas Represoras/genética , Adulto , Niño , Preescolar , Cromosomas Humanos Par 3/genética , Hibridación Genómica Comparativa , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , SíndromeRESUMEN
Generation and subsequently accessibility of secondary findings (SF) in diagnostic practice is a subject of debate around the world and particularly in Europe. The French FIND study has been set up to assess patient/parent expectations regarding SF from exome sequencing (ES) and to collect their real-life experience until 1 year after the delivery of results. 340 patients who had ES for undiagnosed developmental disorders were included in this multicenter mixed study (quantitative N = 340; qualitative N = 26). Three groups of actionable SF were rendered: predisposition to late-onset actionable diseases; genetic counseling; pharmacogenomics. Participants expressed strong interest in obtaining SF and a high satisfaction level when a SF is reported. The medical actionability of the SF reinforced parents' sense of taking action for their child and was seen as an opportunity. While we observed no serious psychological concerns, we showed that these results could have psychological consequences, in particular for late-onset actionable diseases SF, within families already dealing with rare diseases. This study shows that participants remain in favor of accessing SF despite the potential psychological, care, and lifestyle impacts, which are difficult to anticipate. The establishment of a management protocol, including the support of a multidisciplinary team, would be necessary if national policy allows the reporting of these data.
RESUMEN
Monogenic obesity generally results in severe early-onset obesity associated with abnormal feeding behavior and endocrine disorders. We report here an extremely severe case of early-onset obesity associated with hyperphagia in an 11-month-old boy without other signs of a syndromic obesity. He developed severe obstructive sleep apnea, dyslipidemia, hepatic steatosis with cytolysis, and acanthosis nigricans with insulin resistance in the first months of life. Laboratory investigations showed an elevated serum leptin level (80.03 ng/mL, normal range 2.45-6.55 ng/mL). Next-generation sequencing of obesity genes panel identified a novel homozygous intronic variant in leptin receptor gene (LEPR), c.703 + 5G>A, predicting affected splicing that resulted in a frameshift, premature stop, and truncation of the protein beyond the cytokine receptor homology domain 1. The child died at 27 months of age in the absence of available specific drug therapy.
Asunto(s)
Obesidad , Receptores de Leptina , Masculino , Humanos , Preescolar , Lactante , Receptores de Leptina/genética , Obesidad/complicaciones , Obesidad/genética , Muerte , Conducta Alimentaria , Mutación del Sistema de LecturaRESUMEN
Rearrangements of 22q11.2 region, most often deletions and duplications, are responsible for multiple congenital disorders. These rearrangements are involved in syndromes that share some phenotypic similarities. To date, 22q11.2 triplication remains very rare, with few cases described in the literature. Here, we report for the first time the clinical, neurocognitive, social cognition and psychiatric properties of a 6-year-old child with 22q11.2 triplication, in comparison with a patient with 22q11.2 duplication and 16 cases of patients with 22q11.2 deletion. Chromosomal region 22q11.2 seems to be a critical locus for sociability and attentional skills and rearrangements could be interpreted as a predisposing factor for the development of psychotic symptoms (22q11.2 deletion), a protective factor (22q11.2 duplication) or a tendency factor for hypersociability (22q11.2 triplication).
Asunto(s)
Anomalías Múltiples , Síndrome de DiGeorge , Niño , Humanos , Síndrome de DiGeorge/genética , SíndromeRESUMEN
TCF4 gene (18q21.1) encodes for a transcription factor with multiple isoforms playing a critical role during neurodevelopment. Molecular alterations of this gene are associated with Pitt-Hopkins syndrome, a severe condition characterized by intellectual disability, specific facial features and autonomic nervous system dysfunction. We report here three patients presenting with structural variations of the proximal part of TCF4 associated with a mild phenotype. The first patient is a six-years-old girl carrier of a pericentric inversion of chromosome 18, 46,XX,inv(18)(p11.2q21.1). Whole genome sequencing (WGS) characterized the breakpoint at the base-pair level at chr18:1262334_1262336 and chr18:53254747_53254751 (hg19). This latter breakpoint disrupted the proximal promotor region of TCF4 in the first intron of the gene. The second and third patients are a son and his mother, carrier of a 46 kb deletion characterized by high-resolution chromosomal micro-array and WGS (chr:18:53243454_53287927, hg19) encompassing the first three exon of TCF4 gene and including the proximal promotor region. Expression studies on blood lymphocytes in these patients showed a marked decrease of mRNA level for long isoforms of TCF4 and an increased level for shorter isoforms. The patients described here, together with previously reported patients with proximal structural alterations of TCF4, help to delineate a phenotype of mild ID with non-specific facial dysmorphism without characteristic features of PTHS. It also suggests a gradient of phenotypic severity inversely correlated with the number of intact TCF4 promotor regions, with expression of short isoforms compensating in part the loss of longer isoforms.
Asunto(s)
Discapacidad Intelectual , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Facies , Humanos , Hiperventilación/genética , Discapacidad Intelectual/genética , Factor de Transcripción 4/genética , Factor de Transcripción 4/metabolismoRESUMEN
BACKGROUND: Sensory processing atypicalities are frequent in Autism Spectrum Disorder (ASD) and neurodevelopmental disorders (NDD). Different domains of sensory processing appear to be differentially altered in these disorders. In this study, we explored the sensory profile of two clinical cohorts, in comparison with a sample of typically developing children. METHODS: Behavioral responses to sensory stimuli were assessed using the Sensory Processing Measure (parent-report questionnaire). We included 121 ASD children, 17 carriers of the 16p11.2 deletion (Del 16p11.2) and 45 typically developing (TD) children. All participants were aged between 2 and 12 years. Additional measures included the Tactile Defensiveness and Discrimination Test-Revised, Wechsler Intelligence Scales and Autism Diagnostic Observation Schedule (ADOS-2). Statistical analyses included MANCOVA and regression analyses. RESULTS: ASD children score significantly higher on all SPM subscales compared to TD. Del16p11.2 also scored higher than TD on all subscales except for tactile and olfactory/taste processing, in which they score similarly to TD. When assessing sensory modulation patterns (hyper-, hypo-responsiveness and seeking), ASD did not significantly differ from del16p11.2. Both groups had significantly higher scores across all patterns than the TD group. There was no significant association between the SPM Touch subscale and the TDDT-R. LIMITATIONS: Sensory processing was assessed using a parent-report questionnaire. Even though it captures observable behavior, a questionnaire does not assess sensory processing in all its complexity. The sample size of the genetic cohort and the small subset of ASD children with TDDT-R data render some of our results exploratory. Divergence between SPM Touch and TDDT-R raises important questions about the nature of the process that is assessed. CONCLUSIONS: Touch and olfaction/taste seem to be particularly affected in ASD children compared to del16p11.2. These results indicate that parent report measures can provide a useful perspective on behavioral expression. Sensory phenotyping, when combined with neurobiological and psychophysical methods, might have the potential to provide a better understanding of the sensory processing in ASD and in other NDD.
Asunto(s)
Trastorno del Espectro Autista/fisiopatología , Trastorno Autístico/genética , Trastorno Autístico/fisiopatología , Trastornos de los Cromosomas/genética , Trastornos de los Cromosomas/fisiopatología , Individualidad , Discapacidad Intelectual/genética , Discapacidad Intelectual/fisiopatología , Fenotipo , Percepción del Gusto , Percepción del Tacto , Trastorno del Espectro Autista/diagnóstico , Trastorno del Espectro Autista/etiología , Trastorno Autístico/diagnóstico , Niño , Preescolar , Deleción Cromosómica , Trastornos de los Cromosomas/diagnóstico , Cromosomas Humanos Par 16/genética , Cognición , Variaciones en el Número de Copia de ADN , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Discapacidad Intelectual/diagnóstico , Masculino , MutaciónRESUMEN
PIGC (OMIM 601730) encodes the PIGC protein, which is part of an enzyme complex involved in the biosynthesis of the glycosylphosphatidylinositol protein anchor. The other proteins in the complex include PIGA, PIGH, PIGQ, PIGY, PIGP and DPM2. Homozygous and compound heterozygous mutations in PIGC have recently been described to cause severe global developmental delay, intellectual disability, and seizures in two unrelated families, without indication of another system involvement or dysmorphism. Here we describe two siblings, born to second cousin parents, displaying severe psychomotor delay, seizures, organomegaly, cardiopulmonary anomalies, and similar facial dysmorphism. Exome sequencing in the boy revealed a homozygous variant in PIGC gene, c.12_13insTTGTGACTAACA leading to a premature stop codon p.(Gln4_Pro5insLeu*). His affected sister was also found to be homozygous, and their parents were found to be heterozygous. This is the first detailed clinical description of two related patients suggesting that PIGC deficiency can cause a severe recognisable phenotype including multisystem disorders, in association to previously reported severe developmental delay and seizures.
Asunto(s)
Anomalías Múltiples/genética , Discapacidades del Desarrollo/genética , Hexosiltransferasas/deficiencia , Hexosiltransferasas/genética , Discapacidad Intelectual/genética , Proteínas de la Membrana/deficiencia , Proteínas de la Membrana/genética , Convulsiones/genética , Preescolar , Codón de Terminación , Femenino , Heterocigoto , Homocigoto , Humanos , Lactante , Masculino , Mutación , Linaje , Fenotipo , Hermanos , Secuenciación del ExomaRESUMEN
Donohue syndrome (leprechaunism; OMIM *246200) is a rare and often lethal autosomal recessive disease caused by mutations in the INSR gene. We report the case of a 29-year-old pregnant woman, primigravida, who was referred at 33 weeks of gestation for severe intrauterine growth restriction (IUGR). Ultrasound examination found severe IUGR associated with an obstructive hypertrophic cardiomyopathy (HCM), confirmed postnatally. The newborn's blood glucose level fluctuated from fasting hypoglycemia to postprandial hyperglycemia. The infant was found to be homozygous for a novel missense pathogenic variant, c.632C>T (p.T211l), in exon 2 of the INSR gene, predicted to result in an abnormal insulin receptor. To our knowledge, this is the first report of leprechaunism being revealed by IUGR and HCM during the prenatal period. Clinicians should keep in mind that the association of these prenatal signs could indicate leprechaunism and specific early neonatal management could be proposed, in particular with recombinant human insulin-like growth factor-I.
RESUMEN
The EMC1 gene, located on 1p36.13, encodes the subunit 1 of the endoplasmic reticulum-membrane protein complex, a highly conserved and ubiquitous multiprotein transmembrane complex. Pathogenic monoallelic and biallelic variants in EMC1 in humans have been reported only in six families, causing isolated visual impairment or in association with psychomotor retardation and cerebellar atrophy. We report a ten-year-old boy, born to unrelated parents, with early-onset severe global development delay due to novel EMC1 biallelic pathogenic variants. A truncating variant, p.(Tyr378*) and a missense variant, p.(Phe953Ser), located in exon 11 and 23 of EMC1 gene respectively, have been found by reanalysis of exome sequencing data. The proband's phenotype included several signs that overlap with the phenotype of previously reported patients, associating severe global developmental delay, abnormal ophthalmological examination, and postnatal slow-down of the head circumference growth. Some distinguishing clinical signs were observed in comparison to patients from literature, such as autism spectrum disorder, absence of seizures, scoliosis or facial dysmorphic features, thus extending the spectrum of EMC1-related phenotypes. Similarly, brain MRI, performed at 2 years, showed normal cerebellar volume and structure, whereas cerebellar atrophy was described in literature. Moreover, difficulties of clinical differential diagnosis between EMC1-associated disease and other etiologies of global development delay support the importance of large-scale genetic investigations. Our diagnostic approach, through reanalysis of exome sequencing data, highlights the importance of reconsidering initial negative results for patients with a strong suspicion of genetic disease, and to update analytic pipelines in order to improve the diagnostic yield of exome sequencing.
Asunto(s)
Trastorno del Espectro Autista/genética , Discapacidades del Desarrollo/genética , Mutación Missense , Trastornos de la Visión/genética , Trastorno del Espectro Autista/patología , Niño , Discapacidades del Desarrollo/patología , Humanos , Masculino , Fenotipo , Trastornos de la Visión/patologíaRESUMEN
Apparently, balanced chromosomal rearrangements usually have no phenotypic consequences for the carrier. However, in some cases, they may be associated with an abnormal phenotype. We report herein the case of a 4-year-old boy presenting with clinically isolated supravalvular aortic stenosis (SVAS). No chromosomal imbalance was detected by array CGH. The karyotype showed a balanced paracentric chromosome 7 inversion. Breakpoint characterization using paired-end whole-genome sequencing (WGS) revealed an ELN gene disruption in intron 1, accounting for the phenotype. Family study showed that the inversion was inherited, with incomplete penetrance. To our knowledge, this is the first case of a disruption of the ELN gene characterized by WGS. It contributes to refine the genotype-phenotype correlation in ELN disruption. Although this disruption is a rare etiology of SVAS, it cannot be detected by the diagnostic tests usually performed, such as array CGH or sequencing methods (Sanger, panel, or exome sequencing). With the future perspective of WGS as a diagnostic tool, it will be important to include a structural variation analysis in order to detect balanced rearrangements and gene disruption.
RESUMEN
SCN8A encephalopathy is a newly defined epileptic encephalopathy caused by de novo mutations of the SCN8A gene. We report herein a four-year-old boy presenting with severe non-epileptic abnormal movements, of possibly antenatal onset, progressively associated with pharmacoresistant epilepsy and regression, associated with a de novo heterozygous missense mutation of SCN8A. This case shows that paroxysmal non-epileptic episodes of severe tremor and hyperekplexia-like startles and a striking vegetative component can be the first early symptoms of severe SCN8A developmental and epileptic encephalopathy. Clinicians should be aware of these symptoms in order to avoid misdiagnosis and ensure early appropriate therapeutic management. [Published with video sequences on www.epilepticdisorders.com].
Asunto(s)
Encefalopatías , Epilepsia , Hiperekplexia , Enfermedades del Recién Nacido , Canal de Sodio Activado por Voltaje NAV1.6/genética , Temblor , Encefalopatías/diagnóstico , Encefalopatías/genética , Encefalopatías/fisiopatología , Preescolar , Epilepsia/diagnóstico , Epilepsia/genética , Epilepsia/fisiopatología , Humanos , Hiperekplexia/diagnóstico , Hiperekplexia/genética , Hiperekplexia/fisiopatología , Recién Nacido , Enfermedades del Recién Nacido/diagnóstico , Enfermedades del Recién Nacido/genética , Enfermedades del Recién Nacido/fisiopatología , Masculino , Temblor/diagnóstico , Temblor/genética , Temblor/fisiopatologíaRESUMEN
Guillain-Barré syndrome is a rare acute polyradiculoneuropathy. Several variants and unusual presentations have been described, particularly in pediatrics. In most cases, making an early diagnosis is challenging due to the treatments that consist in the rapid administration of intravenous immunoglobulin or plasma exchange. The authors present the case of a 7-year-old boy with an atypical and severe axonal Guillain-Barré syndrome, associated with Mycoplasma pneumonia. When he was admitted, febrile respiratory failure was the main focus, and then he presented signs of acute polyneuropathy with cranial nerve palsy and brief hyperreflexia. Mechanical ventilation was required for 48 days as well as 2 cycles of intravenous immunoglobulin. The authors describe all the medical challenges that the authors encountered. This case highlights the fact that respiratory distress can be the main clinical symptom in children. This delays the establishment of a correct diagnosis, even more so when neurological manifestations are abundant and unusual.