Acromesomelic dysplasia-2C (AMD2C) is characterized by skeletal abnormalities restricted to the limbs; the craniofacial skeleton and axial skeletal structures are normal. The severity of the long bone shortening progresses in a proximal to distal direction. The hands and feet are most severely affected, but the distal phalanges are relative normal. Affected individuals have joint dislocations but the number of joints involved is not constant (summary by Thomas et al., 1996). For a discussion of genetic heterogeneity of acromesomelic dysplasia, see AMD1 (602875).

Greenberg dysplasia (GRBGD), also known as hydrops-ectopic calcification-moth-eaten (HEM) skeletal dysplasia, is a rare autosomal recessive osteochondrodysplasia characterized by gross fetal hydrops, severe shortening of all long bones with a moth-eaten radiographic appearance, platyspondyly, disorganization of chondroosseous calcification, and ectopic ossification centers. It is lethal in utero. Patient fibroblasts show increased levels of cholesta-8,14-dien-3-beta-ol, suggesting a defect of sterol metabolism (summary by Konstantinidou et al., 2008). Herman (2003) reviewed the cholesterol biosynthetic pathway and 6 disorders involving enzyme defects in postsqualene cholesterol biosynthesis: Smith-Lemli-Opitz syndrome (SLOS; 270400), desmosterolosis (602398), X-linked dominant chondrodysplasia punctata (CDPX2; 302960), CHILD syndrome (308050), lathosterolosis (607330), and HEM skeletal dysplasia.