3M syndrome is a rare autosomal recessive disorder that combines intrauterine growth retardation (IUGR) and postnatal growth retardation. Additionally, this syndrome is characterized by dysmorphic facial features (large head, dolichocephaly, frontal bossing, a triangular face, long philtrum and hypoplastic midface) and certain radiological abnormalities. The latter include slender long bones and ribs, foreshortened vertebral bodies, and small pelvis. The name of this disorder comes from the initials of the three researchers (Miller, McKusik, and Malvaux) who first identified it.
The characteristic radiologic findings of 3M syndrome are used to rule out similar disorders such as Silver-Russel syndrome (SRS), particularly the lack of limb length asymmetry that is present in over half of those with autosomal recessive SRS. The severity of symptoms and physical features varies considerably from case to case.
Mutations leading to 3M syndrome were mapped to the CUL7 gene. CUL7 is involved in chondrocyte growth and proliferation; therefore, CUL7 mutations can lead to reduced cell mitosis during the early gestation period and consequently retarded growth.