The 3M syndrome.

3M syndrome (MIM 273750) is an autosomal recessive disorder characterized by pre- and post-natal growth retardation (<-4 SD), facial dysmorphism, large head circumference, normal intelligence and endocrine function. Skeletal changes include long slender tubular bones and tall vertebral bodies. There is no specific treatment. Up till now, mutations in either CUL7 or OBSL1 genes have been identified in this rare disorder. There are no clinical or radiological differences between patients with CUL7 or OBSL1 mutations. CUL7 appears to be the major gene responsible for 3M syndrome accounting for 77.5% of cases while OBSL1 mutations accounts for 16.3%. A few patients have no mutations in these genes suggesting the involvement of a third gene.