Two closely spaced mutations in cis result in Ullrich congenital muscular dystrophy

A 2-year-old boy was diagnosed with Ullrich congenital muscular dystrophy (UCMD) by muscle biopsy. COL6A3 gene analysis by next-generation sequencing revealed two heterozygous splice-site mutations (c.6283-1 G > G/T and c.6310-2 A > A/T), whereas normal mRNA was produced. Genomic DNA analysis revealed two mutations located on the same allele; however, no mutation was detected in either parent. These results indicated that two closely spaced de novo mutations resulted in the autosomal dominant UCMD.