The Phenotype and Genotype of Congenital Myopathies Based on a Large Pediatric Cohort.
Congenital myopathy
Molecular genetics
Muscle biopsy
Natural history
Next-generation sequencing
Journal
Pediatric neurology
ISSN: 1873-5150
Titre abrégé: Pediatr Neurol
Pays: United States
ID NLM: 8508183
Informations de publication
Date de publication:
02 2021
02 2021
Historique:
received:
31
07
2020
revised:
16
09
2020
accepted:
01
11
2020
pubmed:
18
12
2020
medline:
15
12
2021
entrez:
17
12
2020
Statut:
ppublish
Résumé
Congenital myopathies (CMs) are a clinically and genetically heterogeneous group of hereditary muscular disorders. The distribution of genetic and histologic subtypes has been addressed in only a few cohorts, and the relationship between phenotypes and genotypes is only partially understood. This is a retrospective cross-sectional data collection study conducted at a single center. The clinical, histopathological, and molecular characterization of 104 patients with CM is reported. The most common histopathological subtype was core myopathy (42%). Patients with severe endomysial fibrosis were more commonly unable to walk than patients with only a mild-grade endomysial fibrosis (56% vs 16%). Inability to walk was also more prevalent in patients with severe fatty replacement (44% vs 19%). The genetic etiology was more frequently identified among those patients with "specific" histologic findings (74% vs 62%). A definite molecular diagnosis was reached in 65 of 104 patients (62%), with RYR1 (24/104) and TTN (8/104) being the most frequent causative genes. Neonatal onset occurred in 56%. Independent ambulation was achieved by 74%. Patients who walked late were more likely to become wheelchair-dependent. Respiratory support was needed in one of three patients. Gastrostomy placement was required in 15%. Cardiac involvement was observed in 3%, scoliosis in 43%, and intellectual disability in 6%. This study provides an updated picture of the clinical, histopathological, and molecular landscape of CMs. Independently of the causative gene, fibrosis and fatty replacement in muscle biopsy specimens are associated with clinical severity. Mutations in TTN are responsible for a higher proportion of cases than previously thought.
Sections du résumé
BACKGROUND
Congenital myopathies (CMs) are a clinically and genetically heterogeneous group of hereditary muscular disorders. The distribution of genetic and histologic subtypes has been addressed in only a few cohorts, and the relationship between phenotypes and genotypes is only partially understood.
METHODS
This is a retrospective cross-sectional data collection study conducted at a single center. The clinical, histopathological, and molecular characterization of 104 patients with CM is reported.
RESULTS
The most common histopathological subtype was core myopathy (42%). Patients with severe endomysial fibrosis were more commonly unable to walk than patients with only a mild-grade endomysial fibrosis (56% vs 16%). Inability to walk was also more prevalent in patients with severe fatty replacement (44% vs 19%). The genetic etiology was more frequently identified among those patients with "specific" histologic findings (74% vs 62%). A definite molecular diagnosis was reached in 65 of 104 patients (62%), with RYR1 (24/104) and TTN (8/104) being the most frequent causative genes. Neonatal onset occurred in 56%. Independent ambulation was achieved by 74%. Patients who walked late were more likely to become wheelchair-dependent. Respiratory support was needed in one of three patients. Gastrostomy placement was required in 15%. Cardiac involvement was observed in 3%, scoliosis in 43%, and intellectual disability in 6%.
CONCLUSIONS
This study provides an updated picture of the clinical, histopathological, and molecular landscape of CMs. Independently of the causative gene, fibrosis and fatty replacement in muscle biopsy specimens are associated with clinical severity. Mutations in TTN are responsible for a higher proportion of cases than previously thought.
Identifiants
pubmed: 33333461
pii: S0887-8994(20)30355-6
doi: 10.1016/j.pediatrneurol.2020.11.002
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
50-65Informations de copyright
Copyright © 2020 Elsevier Inc. All rights reserved.