Loss-of-Function Mutations in YY1AP1 Lead to Grange Syndrome and a Fibromuscular Dysplasia-Like Vascular Disease: Fibromuscular dysplasia (FMD) is a heterogeneous group of non-atherosclerotic and
non-inflammatory arterial diseases that primarily involves the renal and cerebrovascular
arteries. Grange syndrome is an autosomal-recessive condition characterized by severe
and early-onset vascular disease similar to FMD and variable penetrance of brachydactyly,
syndactyly, bone fragility, and learning disabilities. Exome-sequencing analysis of
DNA from three affected siblings with Grange syndrome identified compound heterozygous
nonsense variants in YY1AP1, and homozygous nonsense or frameshift YY1AP1 variants
were subsequently identified in additional unrelated probands with Grange syndrome.