Molecular Genetics & Genomic Medicine (Nov 2024)

A Novel Splice Site Variant in COL6A1 Causes Ullrich Congenital Muscular Dystrophy in a Consanguineous Malian Family

  • Alassane Baneye Maiga,
  • Ibrahim Pamanta,
  • Salia Bamba,
  • Lassana Cissé,
  • Salimata Diarra,
  • Sidi Touré,
  • Abdoulaye Yalcouyé,
  • Seydou Diallo,
  • Salimata Diallo,
  • Fousseyni Kané,
  • Seybou Hassane Diallo,
  • Hamidou Oumar Ba,
  • Cheick Oumar Guinto,
  • Kenneth Fischbeck,
  • Guida Landoure,
  • Idrissa Ahmadou Cissé,
  • The H3Africa Consortium

DOI
https://doi.org/10.1002/mgg3.70032
Journal volume & issue
Vol. 12, no. 11
pp. n/a – n/a

Abstract

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ABSTRACT Background Congenital muscular dystrophies (CMDs) are diverse early‐onset conditions affecting skeletal muscle and connective tissue. This group includes collagen VI‐related dystrophies such as Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM), caused by mutations in the COL6A1, COL6A2 and COL6A3 genes. We report a consanguineous Malian family with three siblings affected by UCMD due to a novel homozygous splice site variant in the COL6A1 gene. Methods After obtaining consent, three affected siblings and their relatives underwent physical examinations by specialists and laboratory tests where possible. DNA was extracted from peripheral blood for genetic testing, including Whole Exome Sequencing (WES). Putative variants were confirmed through Sanger Sequencing and assessed for pathogenicity using in silico tools. Results The three siblings and their healthy parents, from a consanguineous marriage, presented with early‐onset progressive muscle weakness, walking difficulty, proximal motor deficits, severe muscle atrophy, hypotonia, skeletal deformities, joint hyperlaxity, ankyloses at the elbows and knees, keloid scars and dental crowding. No cardiac involvement was detected and creatine kinase (CK) levels were normal. All had low serum calcium levels, treated with oral supplements. Needle myography indicated myopathic patterns. WES identified a novel splice site variant in the first intron of COL6A1 (c.98‐1G>C), which segregated with the disease within the family. This variant is predicted to cause exon 2 skipping in COL6A1, with a high CADD score of 33 and Splice AI predicting it as deleterious. Conclusion We identified a novel COL6A1 variant in a consanguineous family, highlighting the need for further studies in larger African cohorts to enhance genetic epidemiology and prepare for future therapeutic research.

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