To date, various SRA1 gene variants, p.Pro20Leu, p.Tyr35Asn, p.Arg126His and p.Ile179Thr, have been identified in homozygosity, compound heterozygosity, heterozygosity or as digenically inherited with PNPLA6, RNF216 and SEMA7A gene variants in patients with CHH [38,46,47]. This evidence concerns the gene SEMA7A and cartilage-hair hypoplasia.