SGCD and heart disorder: No patients with LGMDR6 have previously been reported in Japan; here, we report the first identification of Japanese patients with LGMDR6, with biallelic variants in SGCD. Although the reason for the low prevalence of LGMDR6 is unclear, it has been suggested that SGCD is expressed in the heart, and that individuals with variants in SGCD may die in utero [24]; however, no cardiac disease was observed in our patients with LGMDR6, although genetically undiagnosed siblings of F53 are recorded to have died of cardiac disease.