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1.
J Exp Med ; 217(3)2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31914175

RESUMO

The gene IL6ST encodes GP130, the common signal transducer of the IL-6 cytokine family consisting of 10 cytokines. Previous studies have identified cytokine-selective IL6ST defects that preserve LIF signaling. We describe three unrelated families with at least five affected individuals who presented with lethal Stüve-Wiedemann-like syndrome characterized by skeletal dysplasia and neonatal lung dysfunction with additional features such as congenital thrombocytopenia, eczematoid dermatitis, renal abnormalities, and defective acute-phase response. We identified essential loss-of-function variants in IL6ST (a homozygous nonsense variant and a homozygous intronic splice variant with exon skipping). Functional tests showed absent cellular responses to GP130-dependent cytokines including IL-6, IL-11, IL-27, oncostatin M (OSM), and leukemia inhibitory factor (LIF). Genetic reconstitution of GP130 by lentiviral transduction in patient-derived cells reversed the signaling defect. This study identifies a new genetic syndrome caused by the complete lack of signaling of a whole family of GP130-dependent cytokines in humans and highlights the importance of the LIF signaling pathway in pre- and perinatal development.

2.
Genome Med ; 11(1): 68, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31694722

RESUMO

BACKGROUND: Since different types of genetic variants, from single nucleotide variants (SNVs) to large chromosomal rearrangements, underlie intellectual disability, we evaluated the use of whole-genome sequencing (WGS) rather than chromosomal microarray analysis (CMA) as a first-line genetic diagnostic test. METHODS: We analyzed three cohorts with short-read WGS: (i) a retrospective cohort with validated copy number variants (CNVs) (cohort 1, n = 68), (ii) individuals referred for monogenic multi-gene panels (cohort 2, n = 156), and (iii) 100 prospective, consecutive cases referred to our center for CMA (cohort 3). Bioinformatic tools developed include FindSV, SVDB, Rhocall, Rhoviz, and vcf2cytosure. RESULTS: First, we validated our structural variant (SV)-calling pipeline on cohort 1, consisting of three trisomies and 79 deletions and duplications with a median size of 850 kb (min 500 bp, max 155 Mb). All variants were detected. Second, we utilized the same pipeline in cohort 2 and analyzed with monogenic WGS panels, increasing the diagnostic yield to 8%. Next, cohort 3 was analyzed by both CMA and WGS. The WGS data was processed for large (> 10 kb) SVs genome-wide and for exonic SVs and SNVs in a panel of 887 genes linked to intellectual disability as well as genes matched to patient-specific Human Phenotype Ontology (HPO) phenotypes. This yielded a total of 25 pathogenic variants (SNVs or SVs), of which 12 were detected by CMA as well. We also applied short tandem repeat (STR) expansion detection and discovered one pathologic expansion in ATXN7. Finally, a case of Prader-Willi syndrome with uniparental disomy (UPD) was validated in the WGS data. Important positional information was obtained in all cohorts. Remarkably, 7% of the analyzed cases harbored complex structural variants, as exemplified by a ring chromosome and two duplications found to be an insertional translocation and part of a cryptic unbalanced translocation, respectively. CONCLUSION: The overall diagnostic rate of 27% was more than doubled compared to clinical microarray (12%). Using WGS, we detected a wide range of SVs with high accuracy. Since the WGS data also allowed for analysis of SNVs, UPD, and STRs, it represents a powerful comprehensive genetic test in a clinical diagnostic laboratory setting.

3.
Nat Med ; 25(4): 583-590, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30804514

RESUMO

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression. Heterozygous loss-of-function point mutations of miRNA genes are associated with several human congenital disorders1-5, but neomorphic (gain-of-new-function) mutations in miRNAs due to nucleotide substitutions have not been reported. Here we describe a neomorphic seed region mutation in the chondrocyte-specific, super-enhancer-associated MIR140 gene encoding microRNA-140 (miR-140) in a novel autosomal dominant human skeletal dysplasia. Mice with the corresponding single nucleotide substitution show skeletal abnormalities similar to those of the patients but distinct from those of miR-140-null mice6. This mutant miRNA gene yields abundant mutant miR-140-5p expression without miRNA-processing defects. In chondrocytes, the mutation causes widespread derepression of wild-type miR-140-5p targets and repression of mutant miR-140-5p targets, indicating that the mutation produces both loss-of-function and gain-of-function effects. Furthermore, the mutant miR-140-5p seed competes with the conserved RNA-binding protein Ybx1 for overlapping binding sites. This finding may explain the potent target repression and robust in vivo effect by this mutant miRNA even in the absence of evolutionary selection of miRNA-target RNA interactions, which contributes to the strong regulatory effects of conserved miRNAs7,8. Our study presents the first case of a pathogenic gain-of-function miRNA mutation and provides molecular insight into neomorphic actions of emerging and/or mutant miRNAs.


Assuntos
Doenças do Desenvolvimento Ósseo/genética , Mutação com Ganho de Função/genética , MicroRNAs/genética , Animais , Sequência de Bases , Condrócitos/metabolismo , Feminino , Homozigoto , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Mutantes , MicroRNAs/metabolismo , Linhagem , Fenótipo , Transcriptoma/genética
4.
Am J Hum Genet ; 103(4): 553-567, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30290151

RESUMO

The conserved oligomeric Golgi (COG) complex is involved in intracellular vesicular transport, and is composed of eight subunits distributed in two lobes, lobe A (COG1-4) and lobe B (COG5-8). We describe fourteen individuals with Saul-Wilson syndrome, a rare form of primordial dwarfism with characteristic facial and radiographic features. All affected subjects harbored heterozygous de novo variants in COG4, giving rise to the same recurrent amino acid substitution (p.Gly516Arg). Affected individuals' fibroblasts, whose COG4 mRNA and protein were not decreased, exhibited delayed anterograde vesicular trafficking from the ER to the Golgi and accelerated retrograde vesicular recycling from the Golgi to the ER. This altered steady-state equilibrium led to a decrease in Golgi volume, as well as morphologic abnormalities with collapse of the Golgi stacks. Despite these abnormalities of the Golgi apparatus, protein glycosylation in sera and fibroblasts from affected subjects was not notably altered, but decorin, a proteoglycan secreted into the extracellular matrix, showed altered Golgi-dependent glycosylation. In summary, we define a specific heterozygous COG4 substitution as the molecular basis of Saul-Wilson syndrome, a rare skeletal dysplasia distinct from biallelic COG4-CDG.


Assuntos
Síndrome do Cromossomo X Frágil/genética , Transporte Proteico/genética , Proteoglicanas/genética , Proteínas de Transporte Vesicular/genética , Adulto , Substituição de Aminoácidos/genética , Animais , Animais Geneticamente Modificados/genética , Linhagem Celular , Criança , Pré-Escolar , Retículo Endoplasmático/genética , Matriz Extracelular/genética , Feminino , Fibroblastos/patologia , Glicosilação , Complexo de Golgi/genética , Heterozigoto , Humanos , Lactente , Masculino , Peixe-Zebra
5.
Am J Med Genet A ; 176(9): 1819-1829, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30152086

RESUMO

The aims of this study was to construct references for sitting height, leg length, arm span, relative sitting height (sitting height/height), and foot length and to discuss the development for these anthropometric variables in achondroplasia. Sex-specific references covering ±2 SD are presented for ages 2-20 years. Legs and arms in achondroplasia are already at 2 years of age considerably shorter than in the general population and this deviation increases with age. At adult ages, legs are almost 50% shorter than in the general population and arm span roughly 35% shorter. As sitting height is only mildly affected, relative sitting height position develops far beyond normal ranges. Foot length is also not as affected as limbs.


Assuntos
Acondroplasia/diagnóstico , Pesos e Medidas Corporais , Crescimento e Desenvolvimento , Adolescente , Adulto , Braço/crescimento & desenvolvimento , Estatura , Criança , Pré-Escolar , Feminino , Pé/crescimento & desenvolvimento , Gráficos de Crescimento , Humanos , Masculino , Fenótipo , Postura Sentada , Adulto Jovem
6.
Am J Med Genet A ; 176(8): 1723-1734, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30070757

RESUMO

As growth references for achondroplasia are limited to reports from United States, Japan, Argentina, and Australia, the aim of this study was to construct growth references for height, weight, head circumference, and body mass index (BMI) from a European cohort of children with achondroplasia and to discuss the development of these anthropometric variables. A mix of cross-sectional and longitudinal, retrospective, and prospective data from 466 children with achondroplasia and 4,375 measuring occasions were modeled with generalized additive model for location, scale and shape (GAMLSS) to sex-specific references for ages 0 to 20 years. Loss in height position, that is, reduction in height standard deviation scores, occurred mainly during first 2 years of life while pubertal growth seemed normal if related to adult height. Adult height was 132 cm in boys and 124 cm in girls with a variability comparable to that of the general population and seems to be remarkably similar in most studies of children with achondroplasia. BMI had a syndrome-specific development that was not comparable to BMI development in the general population. Weight and BMI might be misleading when evaluating, for example, metabolic health in achondroplasia. Head circumference reached adult head size earlier than in the general population. Increased tempo of head circumference growth necessitates thus close clinical follow-up during first postnatal years.

7.
Hum Mutat ; 39(10): 1456-1467, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30080953

RESUMO

Skeletal dysplasias are a diverse group of rare Mendelian disorders with clinical and genetic heterogeneity. Here, we used targeted copy number variant (CNV) screening and identified intragenic exonic duplications, formed through Alu-Alu fusion events, in two individuals with skeletal dysplasia and negative exome sequencing results. First, we detected a homozygous tandem duplication of exon 9 and 10 in IFT81 in a boy with Jeune syndrome, or short-rib thoracic dysplasia (SRTD) (MIM# 208500). Western blot analysis did not detect any wild-type IFT81 protein in fibroblasts from the patient with the IFT81 duplication, but only a shorter isoform of IFT81 that was also present in the normal control samples. Complementary zebrafish studies suggested that loss of full-length IFT81 protein but expression of a shorter form of IFT81 protein affects the phenotype while being compatible with life. Second, a de novo tandem duplication of exons 2 to 5 in MATN3 was identified in a girl with multiple epiphyseal dysplasia (MED) type 5 (MIM# 607078). Our data highlights the importance of detection and careful characterization of intragenic duplication CNVs, presenting them as a novel and very rare genetic mechanism in IFT81-related Jeune syndrome and MATN3-related MED.


Assuntos
Elementos Alu , Duplicação Gênica , Estudos de Associação Genética , Proteínas Musculares/genética , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/genética , Adolescente , Animais , Criança , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Síndrome de Ellis-Van Creveld/diagnóstico , Síndrome de Ellis-Van Creveld/genética , Feminino , Homozigoto , Humanos , Masculino , Proteínas Matrilinas/genética , Linhagem , Fenótipo , Radiografia , Sequenciamento Completo do Genoma , Peixe-Zebra
9.
Nat Genet ; 50(5): 657-661, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29662165

RESUMO

RNA interference (RNAi) is a major, powerful platform for gene perturbations, but is restricted by off-target mechanisms. Communication between RNAs, small RNAs, and RNA-binding proteins (RBPs) is a pervasive feature of cellular RNA networks. We present a crosstalk scenario, designated as crosstalk with endogenous RBPs' (ceRBP), in which small interfering RNAs or microRNAs with seed sequences that overlap RBP motifs have extended biological effects by perturbing endogenous RBP activity. Systematic analysis of small interfering RNA (siRNA) off-target data and genome-wide RNAi cancer lethality screens using 501 human cancer cell lines, a cancer dependency map, identified that seed-to-RBP crosstalk is widespread, contributes to off-target activity, and affects RNAi performance. Specifically, deconvolution of the interactions between gene knockdown and seed-mediated silencing effects in the cancer dependency map showed widespread contributions of seed-to-RBP crosstalk to growth-phenotype modulation. These findings suggest a novel aspect of microRNA biology and offer a basis for improvement of RNAi agents and RNAi-based functional genomics.


Assuntos
Interferência de RNA , Proteínas de Ligação a RNA/genética , Linhagem Celular Tumoral , Genômica/métodos , Humanos , MicroRNAs/genética , Neoplasias/genética , RNA Interferente Pequeno/genética
10.
J Bone Miner Res ; 33(4): 753-760, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29178448

RESUMO

Osteogenesis imperfecta (OI) is a strikingly heterogeneous group of disorders with a broad range of phenotypic variations. It is also one of the differential diagnoses in bent bone dysplasias along with campomelic dysplasia and thanatophoric dysplasia and can usually be distinguished by decreased bone mineralization and bone fractures. Bent bone dysplasias also include syndromes such as kyphomelic dysplasia (MIM:211350) and mesomelic dysplasia Kozlowski-Reardon (MIM249710), both of which have been under debate regarding whether or not they are a real entity or simply a phenotypic manifestation of another dysplasia including OI. Bruck syndrome type 2 (BRKS2; MIM:609220) is a rare form of autosomal recessive OI caused by biallelic PLOD2 variants and is associated with congenital joint contractures with pterygia. In this report, we present six patients from four families with novel PLOD2 variants. All cases had multiple fractures. Other features ranged from prenatal lethal severe angulation of the long bones as in kyphomelic dysplasia and mesomelic dysplasia Kozlowski-Reardon through classical Bruck syndrome to moderate OI with normal joints. Two siblings with a kyphomelic dysplasia-like phenotype who were stillborn had compound heterozygous variants in PLOD2 (p.Asp585Val and p.Ser166*). One infant who succumbed at age 4 months had a bent bone phenotype phenotypically like skeletal dysplasia Kozlowski-Reardon (with mesomelic shortening, camptodactyly, retrognathia, cleft palate, skin dimples, but also with fractures). He was homozygous for the nonsense variant (p.Trp561*). Two siblings had various degrees of Bruck syndrome caused by the homozygous missense variant, p.His687Arg. Furthermore a boy with a clinical presentation of moderate OI had a possibly pathogenic homozygous variant p.Trp588Cys. Our experience of six patients with biallelic pathogenic variants in PLOD2 expands the phenotypic spectrum in the PLOD2-related phenotypes. © 2017 American Society for Bone and Mineral Research.


Assuntos
Anormalidades Múltiplas , Artrogripose , Doenças do Desenvolvimento Ósseo , Mutação de Sentido Incorreto , Osteogênese Imperfeita , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/genética , Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/genética , Adulto , Substituição de Aminoácidos , Artrogripose/diagnóstico por imagem , Artrogripose/genética , Doenças do Desenvolvimento Ósseo/diagnóstico por imagem , Doenças do Desenvolvimento Ósseo/genética , Feminino , Humanos , Recém-Nascido , Masculino , Osteogênese Imperfeita/diagnóstico por imagem , Osteogênese Imperfeita/genética
12.
PLoS One ; 12(5): e0176466, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28498836

RESUMO

Osteogenesis imperfecta (OI) is a heterogeneous group of disorders of connective tissue, caused mainly by mutations in the collagen I genes (COL1A1 and COL1A2). Dentinogenesis imperfecta (DGI) and other dental aberrations are common features of OI. We investigated the association between collagen I mutations and DGI, taurodontism, and retention of permanent second molars in a retrospective cohort of 152 unrelated children and adolescents with OI. The clinical examination included radiographic evaluations. Teeth from 81 individuals were available for histopathological evaluation. COL1A1/2 mutations were found in 104 individuals by nucleotide sequencing. DGI was diagnosed clinically and radiographically in 29% of the individuals (44/152) and through isolated histological findings in another 19% (29/152). In the individuals with a COL1A1 mutation, 70% (7/10) of those with a glycine substitution located C-terminal of p.Gly305 exhibited DGI in both dentitions while no individual (0/7) with a mutation N-terminal of this point exhibited DGI in either dentition (p = 0.01). In the individuals with a COL1A2 mutation, 80% (8/10) of those with a glycine substitution located C terminal of p.Gly211 exhibited DGI in both dentitions while no individual (0/5) with a mutation N-terminal of this point (p = 0.007) exhibited DGI in either dentition. DGI was restricted to the deciduous dentition in 20 individuals. Seventeen had missense mutations where glycine to serine was the most prevalent substitution (53%). Taurodontism occurred in 18% and retention of permanent second molars in 31% of the adolescents. Dental aberrations are strongly associated with qualitatively changed collagen I. The varying expressivity of DGI is related to the location of the collagen I mutation. Genotype information may be helpful in identifying individuals with OI who have an increased risk of dental aberrations.


Assuntos
Colágeno Tipo I/genética , Dentinogênese Imperfeita/etiologia , Mutação/genética , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/genética , Adolescente , Adulto , Criança , Pré-Escolar , Cavidade Pulpar/anormalidades , Dentinogênese Imperfeita/genética , Feminino , Genótipo , Humanos , Lactente , Masculino , Mutação de Sentido Incorreto/genética , Fenótipo , Estudos Retrospectivos , Anormalidades Dentárias/genética , Adulto Jovem
13.
J Bone Miner Res ; 32(4): 776-783, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28084650

RESUMO

Pseudohypoparathyroidism type Ib (PHP1B) is characterized primarily by resistance to parathyroid hormone (PTH) and thus hypocalcemia and hyperphosphatemia, in most cases without evidence for Albright hereditary osteodystrophy (AHO). PHP1B is associated with epigenetic changes at one or several differentially-methylated regions (DMRs) within GNAS, which encodes the α-subunit of the stimulatory G protein (Gsα) and splice variants thereof. Heterozygous, maternally inherited STX16 or GNAS deletions leading to isolated loss-of-methylation (LOM) at exon A/B alone or at all maternal DMRs are the cause of autosomal dominant PHP1B (AD-PHP1B). In this study, we analyzed three affected individuals, the female proband and her two sons. All three revealed isolated LOM at GNAS exon A/B, whereas the proband's healthy maternal grandmother and uncle showed normal methylation at this locus. Haplotype analysis was consistent with linkage to the STX16/GNAS region, yet no deletion could be identified. Whole-genome sequencing of one of the patients revealed a large heterozygous inversion (1,882,433 bp). The centromeric breakpoint of the inversion is located 7,225 bp downstream of GNAS exon XL, but its DMR showed no methylation abnormality, raising the possibility that the inversion disrupts a regulatory element required only for establishing or maintaining exon A/B methylation. Because our three patients presented phenotypes consistent with PHP1B, and not with PHP1A, the Gsα promoter is probably unaffected by the inversion. Our findings expand the spectrum of genetic mutations that lead to LOM at exon A/B alone and thus biallelic expression of the transcript derived from this alternative first GNAS exon. © 2017 American Society for Bone and Mineral Research.


Assuntos
Cromograninas/genética , Transtornos Cromossômicos/genética , Inversão Cromossômica , Éxons , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Genes Dominantes , Heterozigoto , Pseudo-Hipoparatireoidismo/genética , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Sintaxina 16/genética
14.
J Hum Genet ; 62(4): 503-506, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28123176

RESUMO

Axial spondylometaphyseal dysplasia (axial SMD) is a unique form of SMD characterized by dysplasia of axial skeleton and retinal dystrophy. Recently, C21orf2 has been identified as the first disease gene for axial SMD; however, the presence of genetic heterogeneity is known. In this study, we identified NEK1 as the second disease gene for axial SMD. By whole-exome sequencing in a patient with axial SMD, we identified compound heterozygous mutations of NEK1, c.3107C>G (p.S1036*) and c.3830A>C (p.D1277A), which co-segregated in the family. NEK1 mutations have previously been found in three types of short rib thoracic dystrophy, which have no retinal dystrophy. The skeletal phenotype of our patient was milder than those of previously reported cases with NEK1 mutations and those with axial SMD harboring C21orf2 mutations. Phenotypes associated with NEK1 mutations are variable and the phenotype-genotype corelation in skeletal ciliopathies is challenging.


Assuntos
Mutação , Quinase 1 Relacionada a NIMA/genética , Osteocondrodisplasias/genética , Criança , Proteínas do Citoesqueleto , Estudos de Associação Genética , Humanos , Masculino , Linhagem , Proteínas/genética
15.
Skeletal Radiol ; 45(11): 1557-60, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27544198

RESUMO

Brachyolmia (BO) is a heterogeneous group of skeletal dysplasias with skeletal changes limited to the spine or with minimal extraspinal features. BO is currently classified into types 1, 2, 3, and 4. BO types 1 and 4 are autosomal recessive conditions caused by PAPSS2 mutations, which may be merged together as an autosomal recessive BO (AR-BO). The clinical and radiological signs of AR-BO in late childhood have already been reported; however, the early manifestations and their age-dependent evolution have not been well documented. We report an affected boy with AR-BO, whose skeletal abnormalities were detected in utero and who was followed until 10 years of age. Prenatal ultrasound showed bowing of the legs. In infancy, radiographs showed moderate platyspondyly and dumbbell deformity of the tubular bones. Gradually, the platyspondyly became more pronounced, while the bowing of the legs and dumbbell deformities of the tubular bones diminished with age. In late childhood, the overall findings were consistent with known features of AR-BO. Genetic testing confirmed the diagnosis. Being aware of the initial skeletal changes may facilitate early diagnosis of PAPSS2-related skeletal dysplasias.


Assuntos
Envelhecimento/patologia , Osteocondrodisplasias/diagnóstico por imagem , Osteocondrodisplasias/patologia , Radiografia Torácica/métodos , Criança , Pré-Escolar , Diagnóstico Diferencial , Progressão da Doença , Humanos , Lactente , Masculino
16.
J Bone Miner Res ; 31(8): 1577-85, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26987875

RESUMO

Spondyloocular syndrome is an autosomal-recessive disorder with spinal compression fractures, osteoporosis, and cataract. Mutations in XYLT2, encoding isoform of xylosyltransferase, were recently identified as the cause of the syndrome. We report on 4 patients, 2 unrelated patients and 2 siblings, with spondyloocular syndrome and novel mutations in XYLT2. Exome sequencing revealed a homozygous nonsense mutation, NM_022167.3(XYLT2): c.2188C>T, resulting in a premature stop codon (p.Arg730*) in a female patient. The patient presents visual impairment, generalized osteoporosis, short stature with short trunk, spinal compression fractures, and increased intervertebral disc space and hearing loss. We extended our XYLT2 analysis to a cohort of 22 patients with generalized osteoporosis, mostly from consanguineous families. In this cohort, we found by Sanger sequencing 2 siblings and 1 single patient who were homozygous for missense mutations in the XYLT2 gene (p.Arg563Gly and p.Leu605Pro). The patients had osteoporosis, compression fractures, cataracts, and hearing loss. Bisphosphonate treatment in 1 patient resulted in almost complete normalization of vertebral structures by adolescence, whereas treatment response in the others was variable. This report together with a previous study shows that mutations in the XYLT2 gene result in a variable phenotype dominated by spinal osteoporosis, cataract, and hearing loss. © 2016 American Society for Bone and Mineral Research.


Assuntos
Catarata/genética , Mutação/genética , Osteoporose/genética , Pentosiltransferases/genética , Fraturas da Coluna Vertebral/genética , Adolescente , Catarata/complicações , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Masculino , Osteoporose/complicações , Linhagem , Fenótipo , Fraturas da Coluna Vertebral/complicações , Fraturas da Coluna Vertebral/diagnóstico por imagem , Síndrome , Sequenciamento Completo do Exoma
17.
PLoS One ; 11(3): e0150555, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26974433

RESUMO

Axial spondylometaphyseal dysplasia (axial SMD) is an autosomal recessive disease characterized by dysplasia of axial skeleton and retinal dystrophy. We conducted whole exome sequencing and identified C21orf2 (chromosome 21 open reading frame 2) as a disease gene for axial SMD. C21orf2 mutations have been recently found to cause isolated retinal degeneration and Jeune syndrome. We found a total of five biallelic C21orf2 mutations in six families out of nine: three missense and two splicing mutations in patients with various ethnic backgrounds. The pathogenic effects of the splicing (splice-site and branch-point) mutations were confirmed on RNA level, which showed complex patterns of abnormal splicing. C21orf2 mutations presented with a wide range of skeletal phenotypes, including cupped and flared anterior ends of ribs, lacy ilia and metaphyseal dysplasia of proximal femora. Analysis of patients without C21orf2 mutation indicated genetic heterogeneity of axial SMD. Functional data in chondrocyte suggest C21orf2 is implicated in cartilage differentiation. C21orf2 protein was localized to the connecting cilium of the cone and rod photoreceptors, confirming its significance in retinal function. Our study indicates that axial SMD is a member of a unique group of ciliopathy affecting skeleton and retina.


Assuntos
Doenças Genéticas Inatas/genética , Mutação , Osteocondrodisplasias/genética , Proteínas/genética , Adolescente , Cartilagem/metabolismo , Cartilagem/patologia , Diferenciação Celular/genética , Criança , Pré-Escolar , Proteínas do Citoesqueleto , Feminino , Regulação da Expressão Gênica , Doenças Genéticas Inatas/diagnóstico por imagem , Doenças Genéticas Inatas/metabolismo , Humanos , Masculino , Osteocondrodisplasias/diagnóstico por imagem , Osteocondrodisplasias/metabolismo , Fenótipo , Proteínas/metabolismo , Radiografia , Retina/metabolismo , Retina/patologia , Adulto Jovem
18.
Orphanet J Rare Dis ; 11: 1, 2016 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-26728142

RESUMO

Ischiospinal dysostosis (ISD) is a polytopic dysostosis characterized by ischial hypoplasia, multiple segmental anomalies of the cervicothoracic spine, hypoplasia of the lumbrosacral spine and occasionally associated with nephroblastomatosis. ISD is similar to, but milder than the lethal/semilethal condition termed diaphanospondylodysostosis (DSD), which is associated with homozygous or compound heterozygous mutations of bone morphogenetic protein-binding endothelial regulator protein (BMPER) gene. Here we report for the first time biallelic BMPER mutations in two patients with ISD, neither of whom had renal abnormalities. Our data supports and further extends the phenotypic variability of BMPER-related skeletal disorders.


Assuntos
Proteínas de Transporte/genética , Anormalidades Craniofaciais/diagnóstico , Disostoses/diagnóstico , Disostoses/genética , Costelas/anormalidades , Coluna Vertebral/anormalidades , Adulto , Pré-Escolar , Anormalidades Craniofaciais/genética , Feminino , Humanos , Masculino , Mutação , Adulto Jovem
19.
Eur J Hum Genet ; 24(2): 198-207, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25966638

RESUMO

A rare lethal autosomal recessive syndrome with skeletal dysplasia, polycystic kidneys and multiple malformations was first described by Gillessen-Kaesbach et al and subsequently by Nishimura et al. The skeletal features uniformly comprise a round pelvis, mesomelic shortening of the upper limbs and defective ossification of the cervical spine. We studied two unrelated families including three affected fetuses with Gillessen-Kaesbach-Nishimura syndrome using whole-exome and Sanger sequencing, comparative genome hybridization and homozygosity mapping. All affected patients were shown to have a novel homozygous splice variant NM_024740.2: c.1173+2T>A in the ALG9 gene, encoding alpha-1,2-mannosyltransferase, involved in the formation of the lipid-linked oligosaccharide precursor of N-glycosylation. RNA analysis demonstrated skipping of exon 10, leading to shorter RNA. Mass spectrometric analysis showed an increase in monoglycosylated transferrin as compared with control tissues, confirming that this is a congenital disorder of glycosylation (CDG). Only three liveborn children with ALG9-CDG have been previously reported, all with missense variants. All three suffered from intellectual disability, muscular hypotonia, microcephaly and renal cysts, but none had skeletal dysplasia. Our study shows that some pathogenic variants in ALG9 can present as a lethal skeletal dysplasia with visceral malformations as the most severe phenotype. The skeletal features overlap with that previously reported for ALG3- and ALG12-CDG, suggesting that this subset of glycosylation disorders constitutes a new diagnostic group of skeletal dysplasias.


Assuntos
Anormalidades Múltiplas/genética , Doenças do Desenvolvimento Ósseo/genética , Doenças do Sistema Nervoso Central/genética , Exoma/genética , Manosiltransferases/genética , Proteínas de Membrana/genética , Degeneração Neural/genética , Osteocondrodisplasias/genética , Anormalidades Múltiplas/patologia , Processamento Alternativo/genética , Sequência de Aminoácidos , Doenças do Desenvolvimento Ósseo/fisiopatologia , Doenças do Sistema Nervoso Central/fisiopatologia , Criança , Hibridização Genômica Comparativa , Feminino , Glicosilação , Humanos , Masculino , Mutação de Sentido Incorreto , Degeneração Neural/fisiopatologia , Osteocondrodisplasias/patologia , Fenótipo , Isoformas de Proteínas/genética , Análise de Sequência de RNA
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