A DM1 patient with CCG variant repeats: Reaching the diagnosis.
Multisystem disorder
Myotonic dystrophy
Triplet repeats
Variant repeats
Journal
Neuromuscular disorders : NMD
ISSN: 1873-2364
Titre abrégé: Neuromuscul Disord
Pays: England
ID NLM: 9111470
Informations de publication
Date de publication:
03 2021
03 2021
Historique:
received:
10
07
2020
revised:
12
12
2020
accepted:
14
12
2020
pubmed:
7
2
2021
medline:
16
11
2021
entrez:
6
2
2021
Statut:
ppublish
Résumé
We report the case of a male patient presenting in his 50s with ptosis, facial and distal limb muscle weakness, clinical and electrical myotonia, and a prior history of cataract extraction. He had a dominant family history in keeping with a similar phenotype. Myotonic dystrophy type 1 was clinically suspected. Triplet-primed polymerase chain reaction in a diagnostic laboratory did not identify a typical CTG repeat expansion on two separate blood samples. However, subsequent genetic testing on a research basis identified a heterozygous repeat expansion containing CCG variant repeats. Our case highlights the point that variant repeats are not detectable on triplet-primed polymerase chain reaction and result in a milder phenotype of myotonic dystrophy. It is crucial to maintain a high clinical index of suspicion of this common neuromuscular condition.
Identifiants
pubmed: 33546847
pii: S0960-8966(20)30700-8
doi: 10.1016/j.nmd.2020.12.005
pii:
doi:
Substances chimiques
Myotonin-Protein Kinase
EC 2.7.11.1
Types de publication
Case Reports
Langues
eng
Sous-ensembles de citation
IM
Pagination
232-238Informations de copyright
Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of Competing Interest D.G.M. has been a scientific consultant and/or received honoraria or stock options from Biogen Idec, AMO Pharma, Charles River, Vertex Pharmaceuticals, Triplet Therapeutics, LoQus23, and Small Molecule RNA and has had research contracts with AMO Pharma and Vertex Pharmaceuticals.