Findings in rarer causes of CM include a heterozygous frameshift variant in NAA15, a gene associated with intellectual disability and congenital heart disease, but also found to cause HCM in 2 unrelated children [48]; a homozygous variant in DOLK, which is associated with congenital disorder of glycosylation type Im which includes a DCM phenotype; a homozygous variant in TREX1 which is associated with Aicardi-Goutieres syndrome in which mouse models develop CM; and a homozygous variant in KLHL24, a gene known to be a rare recessive cause of HCM. The gene discussed is KLHL24; the disease is cutaneous mastocytosis.