The clinical spectrum of the congenital myasthenic syndrome resulting from COL13A1 mutations

Pedro M. Rodríguez Cruz*, Judith Cossins, Eduardo De Paula Estephan, Francina Munell, Kathryn Selby, Michio Hirano, Reza Maroofin, Mohammad Yahya Vahidi Mehrjardi, Gabriel Chow, Aisling Carr, Adnan Manzur, Stephanie Robb, Pinki Munot, Wei Wei Liu, Siddharth Banka, Harry Fraser, Christian De Goede, Edmar Zanoteli, Umbertina Conti Reed, Abigail SageMargarida Gratacos, Alfons MacAya, Marina Dusl, Jan Senderek, Ana Töpf, Monika Hofer, Ravi Knight, Sithara Ramdas, Sandeep Jayawant, Hans Lochmüller, Jacqueline Palace, David Beeson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Next generation sequencing techniques were recently used to show mutations in COL13A1 cause synaptic basal lamina-associated congenital myasthenic syndrome type 19. Animal studies showed COL13A1, a synaptic extracellular-matrix protein, is involved in the formation and maintenance of the neuromuscular synapse that appears independent of the Agrin-LRP4-MuSK-DOK7 acetylcholine receptor clustering pathway. Here, we report the phenotypic spectrum of 16 patients from 11 kinships harbouring homozygous or heteroallelic mutations in COL13A1. Clinical presentation was mostly at birth with hypotonia and breathing and feeding difficulties often requiring ventilation and artificial feeding. Respiratory crisis related to recurrent apnoeas, sometimes triggered by chest infections, were common early in life but resolved over time. The predominant pattern of muscle weakness included bilateral ptosis (non-fatigable in adulthood), myopathic facies and marked axial weakness, especially of neck flexion, while limb muscles were less involved. Other features included facial dysmorphism, skeletal abnormalities and mild learning difficulties. All patients tested had results consistent with abnormal neuromuscular transmission. Muscle biopsies were within normal limits or showed non-specific changes. Muscle MRI and serum creatine kinase levels were normal. In keeping with COL13A1 mutations affecting both synaptic structure and presynaptic function, treatment with 3,4-diaminopyridine and salbutamol resulted in motor and respiratory function improvement. In non-treated cases, disease severity and muscle strength improved gradually over time and several adults recovered normal muscle strength in the limbs. In summary, patients with COL13A1 mutations present mostly with severe early-onset myasthenic syndrome with feeding and breathing difficulties. Axial weakness is greater than limb weakness. Disease course improves gradually over time, which could be consistent with the less prominent role of COL13A1 once the neuromuscular junction is mature. This report emphasizes the role of collagens at the human muscle endplate and should facilitate the recognition of this disorder, which can benefit from pharmacological treatment.

Original languageEnglish (US)
Pages (from-to)1547-1560
Number of pages14
JournalBrain
Volume142
Issue number6
DOIs
StatePublished - Jun 1 2019

Keywords

  • 3,4-diaminopyridine
  • COL13A1
  • congenital myasthenic syndromes
  • salbutamol
  • synaptic basal lamina

ASJC Scopus subject areas

  • Clinical Neurology

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