Novel variants broaden the phenotypic spectrum of PLEKHG5-associated neuropathies.
Charcot-Marie-Tooth disease
genotype-phenotype association
hereditary motor neuropathy
hereditary sensory and motor neuropathy
peripheral nerve disease
spinal muscular atrophy
Journal
European journal of neurology
ISSN: 1468-1331
Titre abrégé: Eur J Neurol
Pays: England
ID NLM: 9506311
Informations de publication
Date de publication:
04 2021
04 2021
Historique:
received:
02
10
2020
accepted:
12
11
2020
pubmed:
22
11
2020
medline:
13
8
2021
entrez:
21
11
2020
Statut:
ppublish
Résumé
Pathogenic variants in PLEKHG5 have been reported to date to be causative in three unrelated families with autosomal recessive intermediate Charcot-Marie-Tooth disease (CMT) and in one consanguineous family with spinal muscular atrophy (SMA). PLEKHG5 is known to be expressed in the human peripheral nervous system, and previous studies have shown its function in axon terminal autophagy of synaptic vesicles, lending support to its underlying pathogenetic mechanism. Despite this, there is limited knowledge of the clinical and genetic spectrum of disease. We leverage the diagnostic utility of exome and genome sequencing and describe novel biallelic variants in PLEKHG5 in 13 individuals from nine unrelated families originating from four different countries. We compare our phenotypic and genotypic findings with a comprehensive review of cases previously described in the literature. We found that patients presented with variable disease severity at different ages of onset (8-25 years). In our cases, weakness usually started proximally, progressing distally, and can be associated with intermediate slow conduction velocities and minor clinical sensory involvement. We report three novel nonsense and four novel missense pathogenic variants associated with these PLEKHG5-associated neuropathies, which are phenotypically spinal muscular atrophy (SMA) or intermediate Charcot-Marie-Tooth disease. PLEKHG5-associated neuropathies should be considered as an important differential in non-5q SMAs even in the presence of mild sensory impairment and a candidate causative gene for a wide range of hereditary neuropathies. We present this series of cases to further the understanding of the phenotypic and molecular spectrum of PLEKHG5-associated diseases.
Sections du résumé
BACKGROUND AND PURPOSE
Pathogenic variants in PLEKHG5 have been reported to date to be causative in three unrelated families with autosomal recessive intermediate Charcot-Marie-Tooth disease (CMT) and in one consanguineous family with spinal muscular atrophy (SMA). PLEKHG5 is known to be expressed in the human peripheral nervous system, and previous studies have shown its function in axon terminal autophagy of synaptic vesicles, lending support to its underlying pathogenetic mechanism. Despite this, there is limited knowledge of the clinical and genetic spectrum of disease.
METHODS
We leverage the diagnostic utility of exome and genome sequencing and describe novel biallelic variants in PLEKHG5 in 13 individuals from nine unrelated families originating from four different countries. We compare our phenotypic and genotypic findings with a comprehensive review of cases previously described in the literature.
RESULTS
We found that patients presented with variable disease severity at different ages of onset (8-25 years). In our cases, weakness usually started proximally, progressing distally, and can be associated with intermediate slow conduction velocities and minor clinical sensory involvement. We report three novel nonsense and four novel missense pathogenic variants associated with these PLEKHG5-associated neuropathies, which are phenotypically spinal muscular atrophy (SMA) or intermediate Charcot-Marie-Tooth disease.
CONCLUSIONS
PLEKHG5-associated neuropathies should be considered as an important differential in non-5q SMAs even in the presence of mild sensory impairment and a candidate causative gene for a wide range of hereditary neuropathies. We present this series of cases to further the understanding of the phenotypic and molecular spectrum of PLEKHG5-associated diseases.
Substances chimiques
Guanine Nucleotide Exchange Factors
0
PLEKHG5 protein, human
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
1344-1355Subventions
Organisme : Medical Research Council
ID : MR/N008324/1
Pays : United Kingdom
Commentaires et corrections
Type : CommentIn
Informations de copyright
© 2020 European Academy of Neurology.
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