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1.
Nucleic Acids Res ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38769069

RESUMO

In the era of high throughput sequencing, special software is required for the clinical evaluation of genetic variants. We developed REEV (Review, Evaluate and Explain Variants), a user-friendly platform for clinicians and researchers in the field of rare disease genetics. Supporting data was aggregated from public data sources. We compared REEV with seven other tools for clinical variant evaluation. REEV (semi-)automatically fills individual ACMG criteria facilitating variant interpretation. REEV can store disease and phenotype data related to a case to use these for phenotype similarity measures. Users can create public permanent links for individual variants that can be saved as browser bookmarks and shared. REEV may help in the fast diagnostic assessment of genetic variants in a clinical as well as in a research context. REEV (https://reev.bihealth.org/) is free and open to all users and there is no login requirement.

2.
Hum Genet ; 143(5): 683-694, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38592547

RESUMO

Generalized lipodystrophy is a feature of various hereditary disorders, often leading to a progeroid appearance. In the present study we identified a missense and a frameshift variant in a compound heterozygous state in SUPT7L in a boy with intrauterine growth retardation, generalized lipodystrophy, and additional progeroid features. SUPT7L encodes a component of the transcriptional coactivator complex STAGA. By transcriptome sequencing, we showed the predicted missense variant to cause aberrant splicing, leading to exon truncation and thereby to a complete absence of SUPT7L in dermal fibroblasts. In addition, we found altered expression of genes encoding DNA repair pathway components. This pathway was further investigated and an increased rate of DNA damage was detected in proband-derived fibroblasts and genome-edited HeLa cells. Finally, we performed transient overexpression of wildtype SUPT7L in both cellular systems, which normalizes the number of DNA damage events. Our findings suggest SUPT7L as a novel disease gene and underline the link between genome instability and progeroid phenotypes.


Assuntos
Mutação com Perda de Função , Humanos , Masculino , Células HeLa , Lipodistrofia Generalizada Congênita/genética , Fibroblastos/metabolismo , Dano ao DNA , Mutação de Sentido Incorreto , Reparo do DNA/genética , Lipodistrofia/genética , Fatores de Transcrição/genética , Retardo do Crescimento Fetal/genética
3.
Am J Med Genet A ; 194(7): e63599, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38517182

RESUMO

Pathogenic variants in TRIO, encoding the guanine nucleotide exchange factor, are associated with two distinct neurodevelopmental delay phenotypes: gain-of-function missense mutations within the spectrin repeats are causative for a severe developmental delay with macrocephaly (MIM: 618825), whereas loss-of-function missense variants in the GEF1 domain and truncating variants throughout the gene lead to a milder developmental delay and microcephaly (MIM: 617061). In three affected family members with mild intellectual disability/NDD and microcephaly, we detected a novel heterozygous TRIO variant at the last coding base of exon 31 (NM_007118.4:c.4716G>A). RNA analysis from patient-derived lymphoblastoid cells confirmed aberrant splicing resulting in the skipping of exon 31 (r.4615_4716del), leading to an in-frame deletion in the first Pleckstrin homology subdomain of the GEF1 domain: p.(Thr1539_Lys1572del). To test for a distinct gestalt, facial characteristics of the family members and 41 previously published TRIO cases were systematically evaluated via GestaltMatcher. Computational analysis of the facial gestalt suggests a distinguishable facial TRIO-phenotype not outlined in the existing literature.


Assuntos
Fatores de Troca do Nucleotídeo Guanina , Linhagem , Fenótipo , Sítios de Splice de RNA , Humanos , Fatores de Troca do Nucleotídeo Guanina/genética , Masculino , Feminino , Sítios de Splice de RNA/genética , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Microcefalia/genética , Microcefalia/patologia , Criança , Pré-Escolar , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/patologia , Éxons/genética , Splicing de RNA/genética , Fácies , Proteínas Serina-Treonina Quinases
4.
Eur J Hum Genet ; 31(8): 905-917, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37188825

RESUMO

FINCA syndrome [MIM: 618278] is an autosomal recessive multisystem disorder characterized by fibrosis, neurodegeneration and cerebral angiomatosis. To date, 13 patients from nine families with biallelic NHLRC2 variants have been published. In all of them, the recurrent missense variant p.(Asp148Tyr) was detected on at least one allele. Common manifestations included lung or muscle fibrosis, respiratory distress, developmental delay, neuromuscular symptoms and seizures often followed by early death due to rapid disease progression.Here, we present 15 individuals from 12 families with an overlapping phenotype associated with nine novel NHLRC2 variants identified by exome analysis. All patients described here presented with moderate to severe global developmental delay and variable disease progression. Seizures, truncal hypotonia and movement disorders were frequently observed. Notably, we also present the first eight cases in which the recurrent p.(Asp148Tyr) variant was not detected in either homozygous or compound heterozygous state.We cloned and expressed all novel and most previously published non-truncating variants in HEK293-cells. From the results of these functional studies, we propose a potential genotype-phenotype correlation, with a greater reduction in protein expression being associated with a more severe phenotype.Taken together, our findings broaden the known phenotypic and molecular spectrum and emphasize that NHLRC2-related disease should be considered in patients presenting with intellectual disability, movement disorders, neuroregression and epilepsy with or without pulmonary involvement.


Assuntos
Deficiência Intelectual , Transtornos dos Movimentos , Humanos , Progressão da Doença , Fibrose , Células HEK293 , Deficiência Intelectual/genética , Fenótipo , Convulsões/genética , Síndrome
5.
Rheumatology (Oxford) ; 62(4): 1699-1705, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36193988

RESUMO

OBJECTIVES: Inborn errors of immunity manifest with susceptibility to infection but may also present with immune dysregulation only. According to the European Society for Immunodeficiencies Registry about 50% of inborn errors of immunity are classified as common variable immunodeficiencies (CVID). In only few CVID patients are monogenic causes identified. IFN regulatory factor-2 binding protein 2 (IRF2BP2) is one of 20 known genes associated with CVID phenotypes and has only been reported in two families so far. We report another IRF2BP2-deficient patient with a novel pathogenic variant and phenotype and characterize impaired B cell function and immune dysregulation. METHODS: We performed trio whole-exome sequencing, determined B cell subpopulations and intracellular calcium mobilization upon B cell receptor crosslinking in B cells. T cell subpopulations, T cell proliferation and a type I IFN signature were measured. Colonoscopy and gastroduodenoscopy including histopathology were performed. RESULTS: The 33-year-old male presented with recurrent respiratory infections since childhood, colitis and RA beginning at age 25 years. We identified a novel de novo nonsense IRF2BP2 variant c.1618C>T; p.(Q540*). IgG deficiency was detected as consequence of a severe B cell differentiation defect. This was confirmed by impaired plasmablast formation upon stimulation with CpG. No serum autoantibodies were detected. Intracellular cytokine production in CD4+ T cells and CTLA4 expression on FOXP3+ Tregs were impaired. Type I IFN signature was elevated. CONCLUSION: The identified loss-of-function variant in IRF2BP2 severely impairs B cell development and T cell homeostasis, and may be associated with colitis and RA. Our results provide further evidence for association of IRF2BP2 with CVID and contribute to the understanding of the underlying pathomechanisms.


Assuntos
Linfócitos T CD4-Positivos , Fatores de Transcrição , Masculino , Linfócitos B , Mutação , Fenótipo , Humanos , Adulto
6.
Genet Med ; 24(9): 1927-1940, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35670808

RESUMO

PURPOSE: In this study we aimed to identify the molecular genetic cause of a progressive multisystem disease with prominent lipodystrophy. METHODS: In total, 5 affected individuals were investigated using exome sequencing. Dermal fibroblasts were characterized using RNA sequencing, proteomics, immunoblotting, immunostaining, and electron microscopy. Subcellular localization and rescue studies were performed. RESULTS: We identified a lipodystrophy phenotype with a typical facial appearance, corneal clouding, achalasia, progressive hearing loss, and variable severity. Although 3 individuals showed stunted growth, intellectual disability, and died within the first decade of life (A1, A2, and A3), 2 are adults with normal intellectual development (A4 and A5). All individuals harbored an identical homozygous nonsense variant affecting the retention and splicing complex component BUD13. The nucleotide substitution caused alternative splicing of BUD13 leading to a stable truncated protein whose expression positively correlated with disease expression and life expectancy. In dermal fibroblasts, we found elevated intron retention, a global reduction of spliceosomal proteins, and nuclei with multiple invaginations, which were more pronounced in A1, A2, and A3. Overexpression of both BUD13 isoforms normalized the nuclear morphology. CONCLUSION: Our results define a hitherto unknown syndrome and show that the alternative splice product converts a loss-of-function into a hypomorphic allele, thereby probably determining the severity of the disease and the survival of affected individuals.


Assuntos
Processamento Alternativo , Lipodistrofia , Proteínas de Ligação a RNA/genética , Criança , Deficiências do Desenvolvimento/genética , Humanos , Íntrons , Lipodistrofia/genética , Splicing de RNA
7.
J Clin Endocrinol Metab ; 107(7): e3048-e3057, 2022 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-35276006

RESUMO

CONTEXT: Many different inherited and acquired conditions can result in premature bone fragility/low bone mass disorders (LBMDs). OBJECTIVE: We aimed to elucidate the impact of genetic testing on differential diagnosis of adult LBMDs and at defining clinical criteria for predicting monogenic forms. METHODS: Four clinical centers broadly recruited a cohort of 394 unrelated adult women before menopause and men younger than 55 years with a bone mineral density (BMD) Z-score < -2.0 and/or pathological fractures. After exclusion of secondary causes or unequivocal clinical/biochemical hallmarks of monogenic LBMDs, all participants were genotyped by targeted next-generation sequencing. RESULTS: In total, 20.8% of the participants carried rare disease-causing variants (DCVs) in genes known to cause osteogenesis imperfecta (COL1A1, COL1A2), hypophosphatasia (ALPL), and early-onset osteoporosis (LRP5, PLS3, and WNT1). In addition, we identified rare DCVs in ENPP1, LMNA, NOTCH2, and ZNF469. Three individuals had autosomal recessive, 75 autosomal dominant, and 4 X-linked disorders. A total of 9.7% of the participants harbored variants of unknown significance. A regression analysis revealed that the likelihood of detecting a DCV correlated with a positive family history of osteoporosis, peripheral fractures (> 2), and a high normal body mass index (BMI). In contrast, mutation frequencies did not correlate with age, prevalent vertebral fractures, BMD, or biochemical parameters. In individuals without monogenic disease-causing rare variants, common variants predisposing for low BMD (eg, in LRP5) were overrepresented. CONCLUSION: The overlapping spectra of monogenic adult LBMD can be easily disentangled by genetic testing and the proposed clinical criteria can help to maximize the diagnostic yield.


Assuntos
Osteogênese Imperfeita , Osteoporose , Fraturas da Coluna Vertebral , Adulto , Densidade Óssea/genética , Feminino , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Mutação , Osteogênese Imperfeita/diagnóstico , Osteogênese Imperfeita/genética , Osteoporose/diagnóstico , Osteoporose/genética
8.
Nat Genet ; 54(3): 349-357, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35145301

RESUMO

Many monogenic disorders cause a characteristic facial morphology. Artificial intelligence can support physicians in recognizing these patterns by associating facial phenotypes with the underlying syndrome through training on thousands of patient photographs. However, this 'supervised' approach means that diagnoses are only possible if the disorder was part of the training set. To improve recognition of ultra-rare disorders, we developed GestaltMatcher, an encoder for portraits that is based on a deep convolutional neural network. Photographs of 17,560 patients with 1,115 rare disorders were used to define a Clinical Face Phenotype Space, in which distances between cases define syndromic similarity. Here we show that patients can be matched to others with the same molecular diagnosis even when the disorder was not included in the training set. Together with mutation data, GestaltMatcher could not only accelerate the clinical diagnosis of patients with ultra-rare disorders and facial dysmorphism but also enable the delineation of new phenotypes.


Assuntos
Inteligência Artificial , Doenças Raras , Face , Humanos , Redes Neurais de Computação , Fenótipo , Doenças Raras/genética
9.
J Med Genet ; 59(7): 662-668, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34379057

RESUMO

BACKGROUND: Genes implicated in the Golgi and endosomal trafficking machinery are crucial for brain development, and mutations in them are particularly associated with postnatal microcephaly (POM). METHODS: Exome sequencing was performed in three affected individuals from two unrelated consanguineous families presenting with delayed neurodevelopment, intellectual disability of variable degree, POM and failure to thrive. Patient-derived fibroblasts were tested for functional effects of the variants. RESULTS: We detected homozygous truncating variants in ATP9A. While the variant in family A is predicted to result in an early premature termination codon, the variant in family B affects a canonical splice site. Both variants lead to a substantial reduction of ATP9A mRNA expression. It has been shown previously that ATP9A localises to early and recycling endosomes, whereas its depletion leads to altered gene expression of components from this compartment. Consistent with previous findings, we also observed overexpression of ARPC3 and SNX3, genes strongly interacting with ATP9A. CONCLUSION: In aggregate, our findings show that pathogenic variants in ATP9A cause a novel autosomal recessive neurodevelopmental disorder with POM. While the physiological function of endogenous ATP9A is still largely elusive, our results underline a crucial role of this gene in endosomal transport in brain tissue.


Assuntos
Adenosina Trifosfatases/genética , Deficiência Intelectual , Proteínas de Membrana Transportadoras/genética , Microcefalia , Malformações do Sistema Nervoso , Transtornos do Neurodesenvolvimento , Insuficiência de Crescimento , Homozigoto , Humanos , Deficiência Intelectual/genética , Microcefalia/patologia , Transtornos do Neurodesenvolvimento/genética , Linhagem
10.
NAR Genom Bioinform ; 3(3): lqab078, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34514393

RESUMO

Many rare syndromes can be well described and delineated from other disorders by a combination of characteristic symptoms. These phenotypic features are best documented with terms of the Human Phenotype Ontology (HPO), which are increasingly used in electronic health records (EHRs), too. Many algorithms that perform HPO-based gene prioritization have also been developed; however, the performance of many such tools suffers from an over-representation of atypical cases in the medical literature. This is certainly the case if the algorithm cannot handle features that occur with reduced frequency in a disorder. With Cada, we built a knowledge graph based on both case annotations and disorder annotations. Using network representation learning, we achieve gene prioritization by link prediction. Our results suggest that Cada exhibits superior performance particularly for patients that present with the pathognomonic findings of a disease. Additionally, information about the frequency of occurrence of a feature can readily be incorporated, when available. Crucial in the design of our approach is the use of the growing amount of phenotype-genotype information that diagnostic labs deposit in databases such as ClinVar. By this means, Cada is an ideal reference tool for differential diagnostics in rare disorders that can also be updated regularly.

11.
Genet Med ; 23(4): 679-688, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33442026

RESUMO

PURPOSE: This study aimed to identify the genetic cause of a new multiple congenital anomalies syndrome observed in three individuals from two unrelated families. METHODS: Clinical assessment was conducted prenatally and at different postnatal stages. Genetic studies included exome sequencing (ES) combined with single-nucleotide polymorphism (SNP) array based homozygosity mapping and trio ES. Dermal fibroblasts were used for functional assays. RESULTS: A clinically recognizable syndrome characterized by severe developmental delay, variable brain anomalies, congenital heart defects, dysmorphic facial features, and a distinctive type of synpolydactyly with an additional hypoplastic digit between the fourth and fifth digits of hands and/or feet was identified. Additional features included eye abnormalities, hearing impairment, and electroencephalogram anomalies. ES detected different homozygous truncating variants in MAPKAPK5 in both families. Patient-derived cells showed no expression of MAPKAPK5 protein isoforms and reduced levels of the MAPKAPK5-interacting protein ERK3. F-actin recovery after latrunculin B treatment was found to be less efficient in patient-derived fibroblasts than in control cells, supporting a role of MAPKAPK5 in F-actin polymerization. CONCLUSION: Our data indicate that loss-of-function variants in MAPKAPK5 result in a severe developmental disorder and reveal a major role of this gene in human brain, heart, and limb development.


Assuntos
Deficiências do Desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Serina-Treonina Quinases/genética , Sindactilia , Criança , Deficiências do Desenvolvimento/genética , Humanos , Fenótipo , Sindactilia/genética
12.
Genet Med ; 23(6): 1050-1057, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33495529

RESUMO

PURPOSE: To expand the recent description of a new neurodevelopmental syndrome related to alterations in CDK19. METHODS: Individuals were identified through international collaboration. Functional studies included autophosphorylation assays for CDK19 Gly28Arg and Tyr32His variants and in vivo zebrafish assays of the CDK19G28R and CDK19Y32H. RESULTS: We describe 11 unrelated individuals (age range: 9 months to 14 years) with de novo missense variants mapped to the kinase domain of CDK19, including two recurrent changes at residues Tyr32 and Gly28. In vitro autophosphorylation and substrate phosphorylation assays revealed that kinase activity of protein was lower for p.Gly28Arg and higher for p.Tyr32His substitutions compared with that of the wild-type protein. Injection of CDK19 messenger RNA (mRNA) with either the Tyr32His or the Gly28Arg variants using in vivo zebrafish model significantly increased fraction of embryos with morphological abnormalities. Overall, the phenotype of the now 14 individuals with CDK19-related disorder includes universal developmental delay and facial dysmorphism, hypotonia (79%), seizures (64%), ophthalmologic anomalies (64%), and autism/autistic traits (56%). CONCLUSION: CDK19 de novo missense variants are responsible for a novel neurodevelopmental disorder. Both kinase assay and zebrafish experiments showed that the pathogenetic mechanism may be more diverse than previously thought.


Assuntos
Deficiência Intelectual , Transtornos do Neurodesenvolvimento , Animais , Quinases Ciclina-Dependentes/genética , Mutação com Ganho de Função , Humanos , Lactente , Mutação de Sentido Incorreto , Peixe-Zebra/genética
13.
Brain ; 143(12): 3564-3573, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33242881

RESUMO

KCNN2 encodes the small conductance calcium-activated potassium channel 2 (SK2). Rodent models with spontaneous Kcnn2 mutations show abnormal gait and locomotor activity, tremor and memory deficits, but human disorders related to KCNN2 variants are largely unknown. Using exome sequencing, we identified a de novo KCNN2 frameshift deletion in a patient with learning disabilities, cerebellar ataxia and white matter abnormalities on brain MRI. This discovery prompted us to collect data from nine additional patients with de novo KCNN2 variants (one nonsense, one splice site, six missense variants and one in-frame deletion) and one family with a missense variant inherited from the affected mother. We investigated the functional impact of six selected variants on SK2 channel function using the patch-clamp technique. All variants tested but one, which was reclassified to uncertain significance, led to a loss-of-function of SK2 channels. Patients with KCNN2 variants had motor and language developmental delay, intellectual disability often associated with early-onset movement disorders comprising cerebellar ataxia and/or extrapyramidal symptoms. Altogether, our findings provide evidence that heterozygous variants, likely causing a haploinsufficiency of the KCNN2 gene, lead to novel autosomal dominant neurodevelopmental movement disorders mirroring phenotypes previously described in rodents.


Assuntos
Transtornos dos Movimentos/genética , Transtornos do Neurodesenvolvimento/genética , Canais de Potássio Ativados por Cálcio de Condutância Baixa/genética , Adolescente , Adulto , Ataxia Cerebelar/genética , Ataxia Cerebelar/psicologia , Criança , Pré-Escolar , Fenômenos Eletrofisiológicos , Exoma , Mutação da Fase de Leitura , Variação Genética , Haploinsuficiência , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/psicologia , Deficiências da Aprendizagem/genética , Deficiências da Aprendizagem/psicologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/psicologia , Mutação de Sentido Incorreto/genética , Transtornos do Neurodesenvolvimento/psicologia , Técnicas de Patch-Clamp , Substância Branca/anormalidades , Substância Branca/diagnóstico por imagem , Adulto Jovem
14.
Am J Med Genet A ; 182(9): 2068-2076, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32592542

RESUMO

Hand hyperphalangism leading to shortened index fingers with ulnar deviation, hallux valgus, mild facial dysmorphism and respiratory compromise requiring assisted ventilation are the key features of Chitayat syndrome. This condition results from the recurrent heterozygous missense variant NM_006494.2:c.266A>G; p.(Tyr89Cys) in ERF on chromosome 19q13.2, encoding the ETS2 repressor factor (ERF) protein. The pathomechanism of Chitayat syndrome is unknown. To date, seven individuals with Chitayat syndrome and the recurrent pathogenic ERF variant have been reported in the literature. Here, we describe six additional individuals, among them only one presenting with a history of assisted ventilation, and the remaining presenting with variable pulmonary phenotypes, including one individual without any obvious pulmonary manifestations. Our findings widen the phenotype spectrum caused by the recurrent pathogenic variant in ERF, underline Chitayat syndrome as a cause of isolated skeletal malformations and therefore contribute to the improvement of diagnostic strategies in individuals with hand hyperphalangism.


Assuntos
Dedos/anormalidades , Predisposição Genética para Doença , Hallux Valgus/genética , Síndrome de Pierre Robin/genética , Proteínas Repressoras/genética , Adolescente , Adulto , Criança , Pré-Escolar , Fácies , Feminino , Dedos/diagnóstico por imagem , Dedos/patologia , Hallux Valgus/diagnóstico por imagem , Hallux Valgus/patologia , Humanos , Síndrome de Pierre Robin/diagnóstico por imagem , Síndrome de Pierre Robin/patologia , Sequenciamento do Exoma , Adulto Jovem
15.
Nucleic Acids Res ; 48(W1): W162-W169, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32338743

RESUMO

VarFish is a user-friendly web application for the quality control, filtering, prioritization, analysis, and user-based annotation of DNA variant data with a focus on rare disease genetics. It is capable of processing variant call files with single or multiple samples. The variants are automatically annotated with population frequencies, molecular impact, and presence in databases such as ClinVar. Further, it provides support for pathogenicity scores including CADD, MutationTaster, and phenotypic similarity scores. Users can filter variants based on these annotations and presumed inheritance pattern and sort the results by these scores. Variants passing the filter are listed with their annotations and many useful link-outs to genome browsers, other gene/variant data portals, and external tools for variant assessment. VarFish allows users to create their own annotations including support for variant assessment following ACMG-AMP guidelines. In close collaboration with medical practitioners, VarFish was designed for variant analysis and prioritization in diagnostic and research settings as described in the software's extensive manual. The user interface has been optimized for supporting these protocols. Users can install VarFish on their own in-house servers where it provides additional lab notebook features for collaborative analysis and allows re-analysis of cases, e.g. after update of genotype or phenotype databases.


Assuntos
Variação Genética , Doenças Raras/genética , Software , Humanos , Anotação de Sequência Molecular , Doenças Raras/diagnóstico , Pesquisa , Interface Usuário-Computador
16.
Bone ; 133: 115219, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31923704

RESUMO

Catel-Manzke syndrome is characterized by the combination of Pierre Robin sequence and radial deviation, shortening as well as clinodactyly of the index fingers, due to an accessory ossification center. Mutations in TGDS have been identified as one cause of Catel-Manzke syndrome, but cannot be found as causative in every patient with the clinical diagnosis. We performed a chromosome microarray and/or exome sequencing in three patients with hand hyperphalangism, heart defect, short stature, and mild to severe developmental delay, all of whom were initially given a clinical diagnosis of Catel-Manzke syndrome. In one patient, we detected a large deletion of exons 1-8 and the missense variant c.1282C > T (p.Arg428Trp) in KYNU (NM_003937.2), whereas homozygous missense variants in KYNU were found in the other two patients (c.989G > A (p.Arg330Gln) and c.326G > C (p.Trp109Ser)). Plasma and urine metabolomic analysis of two patients indicated a block along the tryptophan catabolic pathway and urine organic acid analysis showed excretion of xanthurenic acid. Biallelic loss-of-function mutations in KYNU were recently described as a cause of NAD deficiency with vertebral, cardiac, renal and limb defects; however, no hand hyperphalangism was described in those patients, and Catel-Manzke syndrome was not discussed as a differential diagnosis. In conclusion, we present unrelated patients identified with biallelic variants in KYNU leading to kynureninase deficiency and xanthurenic aciduria as a very likely cause of their hyperphalangism, heart defect, short stature, and developmental delay. We suggest performance of urine organic acid analysis in patients with suspected Catel-Manzke syndrome, particularly in those with cardiac or vertebral defects or without mutations in TGDS.


Assuntos
Deformidades Congênitas da Mão , Síndrome de Pierre Robin , Dedos , Deformidades Congênitas da Mão/genética , Homozigoto , Humanos , Mutação/genética
17.
Brain ; 143(1): 55-68, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31834374

RESUMO

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.


Assuntos
Anormalidades Múltiplas/genética , Anormalidades Craniofaciais/genética , Deficiência Intelectual/genética , Transtornos do Desenvolvimento da Linguagem/genética , Malformações do Sistema Nervoso/genética , Transativadores/genética , Proteínas Supressoras de Tumor/genética , Anormalidades Múltiplas/diagnóstico por imagem , Adolescente , Artéria Basilar/anormalidades , Artéria Basilar/diagnóstico por imagem , Artérias Carótidas/anormalidades , Artérias Carótidas/diagnóstico por imagem , Vermis Cerebelar/anormalidades , Vermis Cerebelar/diagnóstico por imagem , Cerebelo/anormalidades , Cerebelo/diagnóstico por imagem , Criança , Pré-Escolar , Estudos de Coortes , Hibridização Genômica Comparativa , Anormalidades Craniofaciais/diagnóstico por imagem , Feminino , Fibroblastos/metabolismo , Humanos , Imageamento Tridimensional , Lactente , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação , Malformações do Sistema Nervoso/diagnóstico por imagem , Degradação do RNAm Mediada por Códon sem Sentido , Polimicrogiria/diagnóstico por imagem , Polimicrogiria/genética , RNA-Seq , Reação em Cadeia da Polimerase em Tempo Real , Síndrome , Tomografia Computadorizada por Raios X , Sequenciamento do Exoma , Sequenciamento Completo do Genoma
18.
Am J Med Genet A ; 182(3): 431-436, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31769200

RESUMO

Catel-Manzke syndrome, also known as micrognathia-digital-syndrome, is a rare autosomal recessive disorder characterized by the combination of the two cardinal features Pierre-Robin sequence and bilateral hyperphalangy leading to ulnar clinodactyly (ulnar curvature of the phalanges) and radial deviation (radial angulation at the metacarpophalangeal joint) of the index fingers. Individuals without one of these major hallmarks or with additional hand malformations have been described as atypical or Catel-Manzke-like syndrome. Biallelic TGDS pathogenic variants have thus far been detected in eight individuals with typical Catel-Manzke syndrome and in one fetus with additional features. Here we report on two individuals with TGDS pathogenic variants who presented with mild radial deviation and ulnar clinodactyly of the index fingers but without radiologic signs of hyperphalangy. Furthermore, both individuals have disproportionate short stature, a feature that has not yet been associated with Catel-Manzke syndrome. Our data broaden the phenotypic spectrum of TGDS-associated Catel-Manzke syndrome and expand the indication for diagnostic testing.


Assuntos
Deformidades Congênitas da Mão/genética , Hidroliases/genética , Síndrome de Pierre Robin/genética , Polidactilia/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/fisiopatologia , Adolescente , Alelos , Criança , Pré-Escolar , Feminino , Deformidades Congênitas da Mão/diagnóstico , Deformidades Congênitas da Mão/fisiopatologia , Humanos , Masculino , Mutação/genética , Síndrome de Pierre Robin/diagnóstico , Síndrome de Pierre Robin/fisiopatologia , Polidactilia/fisiopatologia
19.
Am J Hum Genet ; 105(3): 631-639, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31353024

RESUMO

Notch signaling is an established developmental pathway for brain morphogenesis. Given that Delta-like 1 (DLL1) is a ligand for the Notch receptor and that a few individuals with developmental delay, intellectual disability, and brain malformations have microdeletions encompassing DLL1, we hypothesized that insufficiency of DLL1 causes a human neurodevelopmental disorder. We performed exome sequencing in individuals with neurodevelopmental disorders. The cohort was identified using known Matchmaker Exchange nodes such as GeneMatcher. This method identified 15 individuals from 12 unrelated families with heterozygous pathogenic DLL1 variants (nonsense, missense, splice site, and one whole gene deletion). The most common features in our cohort were intellectual disability, autism spectrum disorder, seizures, variable brain malformations, muscular hypotonia, and scoliosis. We did not identify an obvious genotype-phenotype correlation. Analysis of one splice site variant showed an in-frame insertion of 12 bp. In conclusion, heterozygous DLL1 pathogenic variants cause a variable neurodevelopmental phenotype and multi-systemic features. The clinical and molecular data support haploinsufficiency as a mechanism for the pathogenesis of this DLL1-related disorder and affirm the importance of DLL1 in human brain development.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Haploinsuficiência , Proteínas de Membrana/genética , Transtornos do Neurodesenvolvimento/genética , Estudos de Coortes , Feminino , Humanos , Ligantes , Masculino , Linhagem , Sequenciamento do Exoma
20.
Genet Med ; 21(12): 2807-2814, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31164752

RESUMO

PURPOSE: Phenotype information is crucial for the interpretation of genomic variants. So far it has only been accessible for bioinformatics workflows after encoding into clinical terms by expert dysmorphologists. METHODS: Here, we introduce an approach driven by artificial intelligence that uses portrait photographs for the interpretation of clinical exome data. We measured the value added by computer-assisted image analysis to the diagnostic yield on a cohort consisting of 679 individuals with 105 different monogenic disorders. For each case in the cohort we compiled frontal photos, clinical features, and the disease-causing variants, and simulated multiple exomes of different ethnic backgrounds. RESULTS: The additional use of similarity scores from computer-assisted analysis of frontal photos improved the top 1 accuracy rate by more than 20-89% and the top 10 accuracy rate by more than 5-99% for the disease-causing gene. CONCLUSION: Image analysis by deep-learning algorithms can be used to quantify the phenotypic similarity (PP4 criterion of the American College of Medical Genetics and Genomics guidelines) and to advance the performance of bioinformatics pipelines for exome analysis.


Assuntos
Biologia Computacional/métodos , Processamento de Imagem Assistida por Computador/métodos , Análise de Sequência de DNA/métodos , Algoritmos , Bases de Dados Genéticas , Aprendizado Profundo , Exoma/genética , Feminino , Genômica , Humanos , Masculino , Fenótipo , Software
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