In particular, the boy carries a homozygous missense variant already described as causative of Intellectual developmental disorder, autosomal recessive 58 (MIM: #617270) in the ELP2 gene (NM_001242875.1) (c.1580G>A, p.(Arg527Gln)) [21], and a heterozygous frameshift variant inherited from the father and already reported in association with Hypertrophic cardiomyopathy (MIM: #115197) in MYBPC3 (NM_000256.3) (c.913_914delTT, p.(Phe305Profs*27)) [22]. This evidence concerns the gene MYBPC3 and hypertrophic cardiomyopathy.