AMDM is a type of osteochondrodysplasia which, is clinically characterized with severe dwarfism and shortening of the middle and distal segments of the limbs, as well as having short broad fingers and vertebral abnormalities. Facial appearance and intelligence are normal, and so are birth lengths and weights, but skeletal growth drops sharply after birth.
Diagnosis can be made on the basis of clinical and radiological findings from around the age of two years; with features such as abnormal growth plates and short, misshapen bones in the limbs and spine. Since no major complications occur in the course of the disease, patients only require physiotherapy to control progression of spinal abnormalities. Additionally, psychotherapy can be offered to help patients deal with social challenges.
Faivre et al. (2000) demonstrated linkage to 9p13-q12 in four Turkish consanguineous families with AMDM, but excluded this locus in a fifth Lebanese family, where two sibs, born to first cousin parents, had a mild form of AMDM with less marked shortening of the extremities and almost normal vertebra. Faivre et al. (2000) suggested that genetic heterogeneity accounts for the variable severity of AMDM.