The dilated phenotype subgroup (P.1–P.10) included all patients with Danon disease, the patient with a homozygous ALPK3 variant, carriers of in-frame deletions in TTN and FLNC, a heterozygous TRIM63 missense variant, and carriers of splice-site variants in MYH7 and MYBPC3 (Figure 1 and Figure 2, Table 2). The gene discussed is ALPK3; the disease is Danon disease.