Dystroglycanopathies are a group of Congenital Muscular Dystrophies (CMDs) that span a wide phenotypic spectrum, including late-onset limb-girdle muscular dystrophy, severe muscle–eye–brain disease, Walker–Warburg syndrome, and Fukuyama congenital muscular dystrophy. CMDs are distinguished by genetic heterogeneity in addition to clinical heterogeneity. CMDs have been linked to 18 genes thus far. B3GALNT2, for example, encodes the -1,3- N-acetylgalactosaminyltransferase 2 enzyme that glycosylates-dystroglycan. We found a homozygous frameshift variation in B3GALNT2 due to a mixed uniparental disomy of chromosome 1 in a 7-year-old girl with global developmental delay, significantly delayed active language development, and autistic spectrum disorder, but no indications of muscular dystrophy, using exome sequencing. In addition to this example, we present a summary of all previously reported cases, broadening the phenotypic spectrum even more.
