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1.
Am J Hum Genet ; 105(3): 640-657, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31402090

RESUMO

The identification of genetic variants implicated in human developmental disorders has been revolutionized by second-generation sequencing combined with international pooling of cases. Here, we describe seven individuals who have diverse yet overlapping developmental anomalies, and who all have de novo missense FBXW11 variants identified by whole exome or whole genome sequencing and not reported in the gnomAD database. Their phenotypes include striking neurodevelopmental, digital, jaw, and eye anomalies, and in one individual, features resembling Noonan syndrome, a condition caused by dysregulated RAS signaling. FBXW11 encodes an F-box protein, part of the Skp1-cullin-F-box (SCF) ubiquitin ligase complex, involved in ubiquitination and proteasomal degradation and thus fundamental to many protein regulatory processes. FBXW11 targets include ß-catenin and GLI transcription factors, key mediators of Wnt and Hh signaling, respectively, critical to digital, neurological, and eye development. Structural analyses indicate affected residues cluster at the surface of the loops of the substrate-binding domain of FBXW11, and the variants are predicted to destabilize the protein and/or its interactions. In situ hybridization studies on human and zebrafish embryonic tissues demonstrate FBXW11 is expressed in the developing eye, brain, mandibular processes, and limb buds or pectoral fins. Knockdown of the zebrafish FBXW11 orthologs fbxw11a and fbxw11b resulted in embryos with smaller, misshapen, and underdeveloped eyes and abnormal jaw and pectoral fin development. Our findings support the role of FBXW11 in multiple developmental processes, including those involving the brain, eye, digits, and jaw.

3.
Clin Genet ; 2018 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-30417326

RESUMO

Rett syndrome is rarely suspected in males because of the X-linked dominant inheritance. In the literature, only six male patients have been reported with methyl-CpG-binding protein 2 (MECP2) mosaicism. Next-generation sequencing (NGS) methods have enabled better detection of somatic mosaicism compared to conventional Sanger sequencing; however, mosaics can still be difficult to detect. We present clinical and molecular findings in two males mosaic for a pathogenic MECP2 variant. Both have been reexamined using deep sequencing of DNA isolated from four different cell tissues (blood, muscle, fibroblasts and oral mucosa). Deep sequencing of the different tissues revealed that the variants were present in all tissues. In one patient, the molecular diagnosis could only be established by reexamination after a normal whole exome sequencing, and the other case is an example of reverse genetic diagnostics. Rett syndrome should be considered in males with neurodevelopmental delay and stereotypical hand movements. Subsequent to clinical diagnosis males should be investigated with NGS-based technologies of MECP2 with high read depth and a low threshold for variant calls. If the initial analysis on full blood derived DNA fails to confirm the suspicion, we recommend repeating the analysis on another tissue, preferentially fibroblasts to increase the diagnostic yield.

4.
Am J Hum Genet ; 103(5): 666-678, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30343943

RESUMO

Developmental and epileptic encephalopathies (DEEs) are severe neurodevelopmental disorders often beginning in infancy or early childhood that are characterized by intractable seizures, abundant epileptiform activity on EEG, and developmental impairment or regression. CACNA1E is highly expressed in the central nervous system and encodes the α1-subunit of the voltage-gated CaV2.3 channel, which conducts high voltage-activated R-type calcium currents that initiate synaptic transmission. Using next-generation sequencing techniques, we identified de novo CACNA1E variants in 30 individuals with DEE, characterized by refractory infantile-onset seizures, severe hypotonia, and profound developmental impairment, often with congenital contractures, macrocephaly, hyperkinetic movement disorders, and early death. Most of the 14, partially recurring, variants cluster within the cytoplasmic ends of all four S6 segments, which form the presumed CaV2.3 channel activation gate. Functional analysis of several S6 variants revealed consistent gain-of-function effects comprising facilitated voltage-dependent activation and slowed inactivation. Another variant located in the domain II S4-S5 linker results in facilitated activation and increased current density. Five participants achieved seizure freedom on the anti-epileptic drug topiramate, which blocks R-type calcium channels. We establish pathogenic variants in CACNA1E as a cause of DEEs and suggest facilitated R-type calcium currents as a disease mechanism for human epilepsy and developmental disorders.

6.
Eur J Med Genet ; 56(2): 98-107, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23063575

RESUMO

22q11.2 distal deletion syndrome is distinct from the common 22q11.2 deletion syndrome and caused by microdeletions localized adjacent to the common 22q11 deletion at its telomeric end. Most distal deletions of 22q11 extend from LCR22-4 to an LCR in the range LCR22-5 to LCR22-8. We present three patients with 22q11 distal deletions, of whom two have complex congenital heart malformation, thus broadening the phenotypic spectrum. We compare cardiac malformations reported in 22q11 distal deletion to those reported in the common 22q11 deletion syndrome. We also review the literature for patients with 22q11 distal deletions, and discuss the possible roles of haploinsufficiency of the MAPK1 gene. We find the most frequent features in 22q11 distal deletion to be developmental delay or learning disability, short stature, microcephalus, premature birth with low birth weight, and congenital heart malformation ranging from minor anomalies to complex malformations. Behavioral problems are also seen in a substantial portion of patients. The following dysmorphic features are relatively common: smooth philtrum, abnormally structured ears, cleft palate/bifid uvula, micro-/retrognathia, upslanting palpebral fissures, thin upper lip, and ear tags. Very distal deletions including region LCR22-6 to LCR22-7 encompassing the SMARCB1-gene are associated with an increased risk of malignant rhabdoid tumors.


Assuntos
Síndrome da Deleção 22q11/diagnóstico , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/genética , Fenótipo , Adolescente , Hibridização Genômica Comparativa , Feminino , Estudos de Associação Genética , Humanos , Masculino
7.
Hum Pathol ; 44(5): 683-96, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23063502

RESUMO

The morphologic diagnosis of histiocytic lesions of the gastrointestinal tract can be challenging, and several disorders have to be considered in their differential diagnosis. We present one of the most widespread examples of xanthomatosis of the gastrointestinal tract published so far and give a short review on histiocytic disorders of the gastrointestinal tract in general. The primary histiocytic disorders of uncertain origin, Rosai-Dorfman disease, Langerhans cell histiocytosis, and Erdheim-Chester disease, are addressed. Reactive and infectious conditions such as xanthomatosis, xanthogranulomatous inflammation, juvenile xanthogranuloma, Whipple's disease and malacoplakia are discussed as well. We also briefly go into primary histiocytic disorders of neoplastic origin, systemic diseases with secondary gastrointestinal tract involvement like the lysosomal storage disorders, and pigmented lesions. Using a panel of histochemical stains and immunohistochemical markers, together with conventional microscopy, clinical information, and imaging studies, the diagnosis of histiocytic disorders of the gastrointestinal tract can be established in most instances.


Assuntos
Gastroenteropatias/patologia , Histiócitos/patologia , Histiocitose/patologia , Adulto , Pré-Escolar , Diagnóstico Diferencial , Doença de Erdheim-Chester/patologia , Trato Gastrointestinal/patologia , Histiocitose de Células de Langerhans/patologia , Histiocitose Sinusal/patologia , Humanos , Imuno-Histoquímica , Doenças por Armazenamento dos Lisossomos/patologia , Malacoplasia/patologia , Masculino , Doença de Tangier/patologia , Doença de Whipple/patologia , Xantogranuloma Juvenil/patologia , Xantomatose/complicações , Xantomatose/patologia , Adulto Jovem
8.
Eur J Med Genet ; 55(10): 564-7, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22750323

RESUMO

We present a de novo 1.4 Mb deletion of chromosome 19p13.11-p13.12 in a 16 year old boy with intellectual disability, autistic features, microcephaly, hearing impairment, hypertrichosis, synophrys, protruding front teeth, and other dysmorphic features. By comparing our patient to reported cases with overlapping deletions, we have refined the minimal critical region of hypertrichosis, synophrys, and protruding front teeth to 305 kb, a region containing seven genes. CASP14, which is considered a good candidate gene for hypertrichosis, is not included in this region, questioning the causal relationship.


Assuntos
Anormalidades Múltiplas/genética , Deleção Cromossômica , Cromossomos Humanos Par 19/genética , Sobrancelhas/anormalidades , Hipertricose/genética , Deficiência Intelectual/genética , Anormalidades Dentárias/genética , Adolescente , Caspases/genética , Loci Gênicos , Humanos , Masculino
9.
Clin Dysmorphol ; 21(1): 45-7, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21857505

RESUMO

Trisomy 14 mosaicism is a well-known but rare chromosomal defect with most frequently reported features being growth retardation, psychomotor retardation, broad nose, dysplastic and/or apparently low set ears, micrognathia, short neck, congenital heart disease and, in males, micropenis and cryptorchidism. Other frequent findings are prominent forehead, hyperteleorism, narrow palpebral fissures, large mouth, cleft or highly arched palate, body asymmetry and abnormal skin-pigmentation (Fujimoto et al., 1992). To the best of our knowledge, only one adult patient with trisomy 14 mosaicism has been described so far (Fujimoto et al., 1992). We present the clinical findings in a 27-year-old woman to add to the knowledge of the adult phenotype of trisomy 14 mosaicism and to demonstrate the findings on fibroblast culture.


Assuntos
Trissomia/diagnóstico , Trissomia/genética , Adulto , Estatura/genética , Cromossomos Humanos Par 14/genética , Análise Citogenética , Feminino , Humanos , Cariotipagem , Mosaicismo , Fenótipo , Pigmentação da Pele/genética
10.
BMC Med Genet ; 12: 79, 2011 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-21639936

RESUMO

BACKGROUND: Epidermal nevi (EN) represent benign congenital skin lesions following the lines of Blaschko. They result from genetic mosaicism, and activating FGFR3 and PIK3CA mutations have been implicated. CASE PRESENTATION: We report a female patient with a systemic keratinocytic nevus also involving the oral mucosa. Molecular genetic analysis revealed a mosaicism of the FGFR3 hotspot mutation R248C in the EN lesions of the skin and of the oral mucosa. The detection of the R248C mutation in a proportion of blood leukocytes and a slight scoliosis suggest an EN syndrome. CONCLUSIONS: Our results show that activating FGFR3 mutations can also affect the oral mucosa and that extracutaneous manifestations of EN syndrome can be subtle. We highlight the theoretical risk of the patient having an offspring with thanatophoric dysplasia as gonadal mosaicism for the R248C mutation cannot be excluded.


Assuntos
Epiderme/patologia , Mucosa Bucal/patologia , Mutação de Sentido Incorreto/genética , Nevo/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Feminino , Humanos , Mosaicismo
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