Novel CUL7 biallelic mutations alter the skeletal phenotype of 3M syndrome

3M syndrome is an autosomal recessive disorder characterized by severe growth retardation, distinct facial features, and skeletal changes, including long slender tubular bones and tall vertebral bodies. We report a Japanese patient with 3M syndrome caused by the biallelic novel variants c.1705_1708del and c.1989_1999del of CUL7. Skeletal features were consistent with 3M syndrome in the early neonatal period but became less obvious by 2 years of age.