Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Genet Med ; : 101271, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39305161

RESUMO

PURPOSE: Families living with mitochondrial diseases (MD) often endure prolonged diagnostic journeys and invasive testing, yet many remain without a molecular diagnosis. The Australian Genomics Mitochondrial flagship, comprising clinicians, diagnostic, and research scientists, conducted a prospective national study to identify the diagnostic utility of singleton genomic sequencing using blood samples. METHODS: 140 children and adults living with suspected MD were recruited using modified Nijmegen criteria (MNC) and randomized to either exome + mtDNA sequencing (ES+mtDNAseq) or genome sequencing (GS). RESULTS: Diagnostic yield was 55% (n=77) with variants in nuclear (n=37) and mtDNA (n=18) MD genes, as well as phenocopy genes (n=22). A nuclear gene etiology was identified in 77% of diagnoses, irrespective of disease onset. Diagnostic rates were higher in pediatric-onset (71%) than adult-onset (31%) cases, and comparable in children with non-European (78%) versus European (67%) ancestry. For children, higher MNC scores correlated with increased diagnostic yield and fewer diagnoses in phenocopy genes. Additionally, three adult patients had a mtDNA deletion discovered in skeletal muscle that was not initially identified in blood. CONCLUSION: Genomic sequencing from blood can simplify the diagnostic pathway for individuals living with suspected MD, especially those with childhood onset diseases and high MNC scores.

2.
Hum Mol Genet ; 30(22): 2068-2081, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34170319

RESUMO

Primary autosomal recessive microcephaly and Seckel syndrome spectrum disorders (MCPH-SCKS) include a heterogeneous group of autosomal recessive inherited diseases characterized by primary (congenital) microcephaly, the absence of visceral abnormalities, and a variable degree of cognitive impairment, short stature and facial dysmorphism. Recently, biallelic variants in the nuclear pore complex (NPC) component nucleoporin 85 gene (NUP85) were reported to cause steroid-resistant nephrotic syndrome (SRNS). Here, we report biallelic variants in NUP85 in two pedigrees with an MCPH-SCKS phenotype spectrum without SRNS, thereby expanding the phenotypic spectrum of NUP85-linked diseases. Structural analysis predicts the identified NUP85 variants cause conformational changes that could have an effect on NPC architecture or on its interaction with other NUPs. We show that mutant NUP85 is, however, associated with a reduced number of NPCs but unaltered nucleocytoplasmic compartmentalization, abnormal mitotic spindle morphology, and decreased cell viability and proliferation in one patient's cells. Our results also indicate the link of common cellular mechanisms involved in MCPH-SCKS spectrum disorders and NUP85-associated diseases. In addition to the previous studies, our results broaden the phenotypic spectrum of NUP85-linked human disease and propose a role for NUP85 in nervous system development.


Assuntos
Nanismo/diagnóstico , Nanismo/genética , Microcefalia/diagnóstico , Microcefalia/genética , Mutação , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Fenótipo , Encéfalo/anormalidades , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Fibroblastos/metabolismo , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Lactente , Recém-Nascido , Masculino , Complexo de Proteínas Formadoras de Poros Nucleares/química , Linhagem , Síndrome
3.
Neurobiol Dis ; 153: 105329, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33711494

RESUMO

Children with severe intellectual disability have an increased prevalence of refractory seizures. Steroid treatment may improve seizure outcomes, but the mechanism remains unknown. Here we demonstrate that short term, daily delivery of an exogenous steroid 17ß-estradiol (40 ng/g) in early postnatal life significantly reduced the number and severity of seizures, but did not improve behavioural deficits, in mice modelling mutations in the Aristaless-related homeobox gene (ARX), expanding the first (PA1) or second (PA2) polyalanine tract. Frequency of observed seizures on handling (n = 14/treatment/genotype) were significantly reduced in PA1 (32% reduction) and more modestly reduced in PA2 mice (14% reduction) with steroid treatment compared to vehicle. Spontaneous seizures were assessed (n = 7/treatment/genotype) at 7 weeks of age coinciding with a peak of seizure activity in untreated mice. PA1 mice treated with steroids no longer present with the most severe category of prolonged myoclonic seizures. Treated PA2 mice had an earlier onset of seizures coupled with a subsequent reduction in seizures later in postnatal life, with a complete absence of any seizures during the analysis at 7 weeks of age. Despite the reduction in seizures, 17ß-estradiol treated mice showed no improvement in behavioural or cognitive outcomes in adulthood. For the first time we show that these deficits due to mutations in Arx are already present before seizure onset and do not worsen with seizures. ARX is a transcription factor and Arx PA mutant mice have deregulated transcriptome profiles in the developing embryonic brain. At postnatal day 10, treatment completion, RNAseq identified 129 genes significantly deregulated (Log2FC > ± 0.5, P-value<0.05) in the frontal cortex of mutant compared to wild-type mice. This list reflects genes deregulated in disease and was particularly enriched for known genes in neurodevelopmental disorders and those involved in signalling and developmental pathways. 17ß-estradiol treatment of mutant mice significantly deregulated 295 genes, with only 23 deregulated genes overlapping between vehicle and steroid treated mutant mice. We conclude that 17ß-estradiol treatment recruits processes and pathways to reduce the frequency and severity of seizures in the Arx PA mutant mice but does not precisely correct the deregulated transcriptome nor improve mortality or behavioural and cognitive deficits.


Assuntos
Comportamento Animal/efeitos dos fármacos , Estradiol/farmacologia , Estrogênios/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Homeodomínio/genética , Convulsões/genética , Fatores de Transcrição/genética , Animais , Animais Recém-Nascidos , Intervenção Médica Precoce , Regulação da Expressão Gênica/genética , Humanos , Recém-Nascido , Deficiência Intelectual/genética , Deficiência Intelectual/fisiopatologia , Camundongos , Transtornos do Neurodesenvolvimento/genética , Peptídeos/genética , Convulsões/fisiopatologia , Espasmos Infantis/genética , Espasmos Infantis/fisiopatologia
4.
Mol Genet Metab ; 131(1-2): 197-205, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32739280

RESUMO

The cause of neurodegeneration in MPS mouse models is the focus of much debate and what the underlying cause of disease pathology in MPS mice is. The timing of development of pathology and when this can be reversed or impacted is the key to developing suitable therapies in MPS. This study is the first of its kind to correlate the biochemical changes with the functional outcome as assessed using non-invasive behaviour testing across multiple mucopolysaccharidosis (MPS) mouse models. In the MPS brain, the primary lysosomal enzyme dysfunction leads to accumulation of primary glycosaminoglycans (GAGs) with gangliosides (GM2 and GM3) being the major secondary storage products. With a focus on the neuropathology, a time course experiment was conducted in MPS I, MPS IIIA, MPS VII (severe and attenuated models) in order to understand the relative timing and level of GAG and ganglioside accumulation and how this correlates to behaviour deficits. Time course analysis from 1 to 6 months of age was conducted on brain samples to assess primary GAG (uronic acid), ß-hexosaminidase enzyme activity and levels of GM2 and GM3 gangliosides. This was compared to a battery of non-invasive behaviour tests including open field, inverted grid, rotarod and water cross maze were assessed to determine effects on motor function, activity and learning ability. The results show that the GAG and ganglioside accumulation begins prior to the onset of detectable changes in learning ability and behaviour. Interestingly, the highest levels of GAG and ganglioside accumulation was observed in the MPS IIIA mouse despite having 3% residual enzyme activity. Deficits in motor function were clearly observed in the severe Gusmps/mps, which were significantly delayed in the attenuated Gustm(L175F)Sly model despite their minimal increase in detectable enzyme activity. This suggests that genotype and residual enzyme activity are not indicative of severity of disease pathology in MPS disease and there exists a window when there are considerable storage products without detectable functional deficits which may allow an alteration to occur with therapy.


Assuntos
Encéfalo/metabolismo , Glucuronidase/genética , Mucopolissacaridose III/metabolismo , Mucopolissacaridose I/metabolismo , Mucopolissacaridose VII/metabolismo , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Gangliosídeo G(M2)/genética , Gangliosídeo G(M2)/metabolismo , Gangliosídeo G(M3)/genética , Gangliosídeo G(M3)/metabolismo , Glicosaminoglicanos/genética , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Humanos , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Mucopolissacaridose I/genética , Mucopolissacaridose I/patologia , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Mucopolissacaridose VII/genética , Mucopolissacaridose VII/patologia
5.
Mol Genet Metab ; 124(2): 135-142, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29747998

RESUMO

Short stature is a characteristic feature of most of the mucopolysaccharidoses, a group of inherited lysosomal storage disorders caused by a single enzyme deficiency. MPS patients present with progressive skeletal defects from an early age, including short stature due to impaired cartilage-to-bone conversion (endochondral ossification). The aim of this study was to determine which murine MPS model best reproduces the bone length reduction phenotype of human MPS and use this model to determine the earliest developmental stage when disrupted endochondral ossification first appears. Gusmps/mps mice representing severe MPS VII displayed the greatest reduction in bone elongation and were chosen for histopathological analysis. Tibial development was assessed from E12.5 to 6 months of age. Chondrocytes in the region of the future primary ossification center became hypertrophic at a similar age to normal in the MPS VII mouse fetus, but a delay in bone deposition was observed with an approximate 1 day delay in the formation of the primary ossification centre. Likewise, chondrocytes in the region of the future secondary ossification center also became hypertrophic at the same age as normal in the MPS VII early postnatal mouse. Bone deposition in the secondary ossification centre was delayed by two days in the MPS VII proximal tibia (observed at postnatal day 14 (P14) compared to P12 in normal). The thickness of the tibial growth plate was larger in MPS VII mice from P9 onwards. Abnormal endochondral ossification starts in utero in MPS VII and worsens with age. It is characterized by a normal timeframe for chondrocyte hypertrophy but a delay in the subsequent deposition of bone in both the primary and secondary ossification centres, accompanied by an increase in growth plate thickness. This suggests that the signals for vascular invasion and bone deposition, some of which are derived from hypertrophic chondrocytes, are altered in MPS VII.


Assuntos
Doenças Ósseas/etiologia , Doenças Ósseas/patologia , Modelos Animais de Doenças , Mucopolissacaridose VII/complicações , Osteogênese , Tíbia/patologia , Animais , Animais Recém-Nascidos , Diferenciação Celular , Feminino , Masculino , Camundongos , Gravidez
6.
Neurobiol Dis ; 105: 245-256, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28602636

RESUMO

The Aristaless-related homeobox gene (ARX) is a known intellectual disability (ID) gene that frequently presents with X-linked infantile spasm syndrome as a comorbidity. ID with epilepsy in children is a chronic and devastating disorder that has poor treatment options and disease outcomes. To gain a better understanding of the role that mutations in ARX play in ID and epilepsy, we investigate ARX patient mutations modelled in mice. Over half of all ARX mutations result from expansions of the first two polyalanine (PA1 and PA2 respectively) tracts. However, phenotypic data for the mouse modelling the more frequent ARX PA2 dup24 mutation in patients has not been reported and constitutes a barrier to understanding the molecular mechanisms involved. Here we report the first comprehensive analysis of postnatal outcomes for mice modelling disease-causing expansions to both PA1 and PA2 tracts. Both strains were found to have impaired learning and memory, reduced activity, increased anxiety and reduced sociability; with PA1 mice generally displaying greater behavioural deficits in keeping with the more severe phenotype reported in patients. In agreement with previous reports, 70% of PA1 males exhibit myoclonic seizures by two months of age, with the first observed at P18. In this report, we show 80% of PA2 males also display myoclonic seizures, with the first observed at P19. Consistent with patient phenotypes, we observe large variations in seizure progression and severity for both PA1 and PA2 individual mice. The generation of this comprehensive baseline data is a necessary step on the path to the development of therapies to improve patient outcomes.


Assuntos
Epilepsia/genética , Epilepsia/fisiopatologia , Proteínas de Homeodomínio/metabolismo , Deficiência Intelectual/genética , Deficiência Intelectual/fisiopatologia , Peptídeos/genética , Fatores de Transcrição/metabolismo , Fatores Etários , Animais , Modelos Animais de Doenças , Eletroencefalografia , Feminino , Lateralidade Funcional , Genótipo , Proteínas de Homeodomínio/genética , Masculino , Transtornos Mentais/etiologia , Transtornos Mentais/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Comportamento Social , Estatísticas não Paramétricas , Fatores de Transcrição/genética , Gravação em Vídeo
8.
Genome Biol ; 24(1): 118, 2023 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-37198692

RESUMO

Predicting the impact of coding and noncoding variants on splicing is challenging, particularly in non-canonical splice sites, leading to missed diagnoses in patients. Existing splice prediction tools are complementary but knowing which to use for each splicing context remains difficult. Here, we describe Introme, which uses machine learning to integrate predictions from several splice detection tools, additional splicing rules, and gene architecture features to comprehensively evaluate the likelihood of a variant impacting splicing. Through extensive benchmarking across 21,000 splice-altering variants, Introme outperformed all tools (auPRC: 0.98) for the detection of clinically significant splice variants. Introme is available at https://github.com/CCICB/introme .


Assuntos
Sítios de Splice de RNA , Splicing de RNA , Humanos , Íntrons , Aprendizado de Máquina , Mutação
9.
Nat Med ; 29(1): 180-189, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36658419

RESUMO

Pregnancy loss and perinatal death are devastating events for families. We assessed 'genomic autopsy' as an adjunct to standard autopsy for 200 families who had experienced fetal or newborn death, providing a definitive or candidate genetic diagnosis in 105 families. Our cohort provides evidence of severe atypical in utero presentations of known genetic disorders and identifies novel phenotypes and disease genes. Inheritance of 42% of definitive diagnoses were either autosomal recessive (30.8%), X-linked recessive (3.8%) or autosomal dominant (excluding de novos, 7.7%), with risk of recurrence in future pregnancies. We report that at least ten families (5%) used their diagnosis for preimplantation (5) or prenatal diagnosis (5) of 12 pregnancies. We emphasize the clinical importance of genomic investigations of pregnancy loss and perinatal death, with short turnaround times for diagnostic reporting and followed by systematic research follow-up investigations. This approach has the potential to enable accurate counseling for future pregnancies.


Assuntos
Aborto Espontâneo , Morte Perinatal , Gravidez , Humanos , Feminino , Morte Perinatal/etiologia , Autopsia , Aborto Espontâneo/genética , Diagnóstico Pré-Natal , Genômica
10.
J Bone Miner Res ; 38(5): 692-706, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36896612

RESUMO

Lethal short-limb skeletal dysplasia Al-Gazali type (OMIM %601356), also called dysplastic cortical hyperostosis, Al-Gazali type, is an ultra-rare disorder previously reported in only three unrelated individuals. The genetic etiology for Al-Gazali skeletal dysplasia has up until now been unknown. Through international collaborative efforts involving seven clinical centers worldwide, a cohort of nine patients with clinical and radiographic features consistent with short-limb skeletal dysplasia Al-Gazali type was collected. The affected individuals presented with moderate intrauterine growth restriction, relative macrocephaly, hypertrichosis, large anterior fontanelle, short neck, short and stiff limbs with small hands and feet, severe brachydactyly, and generalized bone sclerosis with mild platyspondyly. Biallelic disease-causing variants in ADAMTSL2 were detected using massively parallel sequencing (MPS) and Sanger sequencing techniques. Six individuals were compound heterozygous and one individual was homozygous for pathogenic variants in ADAMTSL2. In one of the families, pathogenic variants were detected in parental samples only. Overall, this study sheds light on the genetic cause of Al-Gazali skeletal dysplasia and identifies it as a semi-lethal part of the spectrum of ADAMTSL2-related disorders. Furthermore, we highlight the importance of meticulous analysis of the pseudogene region of ADAMTSL2 where disease-causing variants might be located. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).


Assuntos
Doenças do Desenvolvimento Ósseo , Deformidades Congênitas dos Membros , Osteocondrodisplasias , Humanos , Doenças do Desenvolvimento Ósseo/genética , Deformidades Congênitas dos Membros/genética , Deformidades Congênitas dos Membros/patologia , Osteocondrodisplasias/genética , Osso e Ossos/patologia , Homozigoto , Proteínas ADAMTS/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA