Acromesomelic Dysplasia

Extremely short stature as a result of acromesomelic dysplasia of the limbs (forearms, forelegs, hands, feet). In general, patients present with normal intelligence. Joint dislocations may occur. Normal craniofacial and axial skeleton. Care with positioning.

Acromesomelic Dwarfism; AMD.

• Type I = Maroteaux (AMDM) type
• Type II = Hunter-Thompson (AMDH) type
• Type III = Chondrodysplasia Grebe Type
• Type IV = Brahimi Bacha type or Algerian type
• Type V = Campailla Martinelli type or Italian type

Autosomal recessive. The AMDM gene has not yet been identified, but a mutation at the location 9p13-q12 appears to be the most likely cause. In 1996 the AMDH gene was identified as a mutation in cartilage-derived morphogenetic protein 1 (CDMP-1), which has been mapped to 20q11.2.

The genetic mutation leads to abnormal linear growth of the skeleton.

Characteristic clinical and radiographic features in infancy.

Type I: Maroteaux Type (Amdm)

Skeletal disorder that affects the limbs and the spine. Newborns affected with AMDM generally are of normal weight, length, and head circumference but can have short-appearing limbs. Older children and adults are significantly shorter than their peers, generally of normal intelligence, and are not expected to have any additional medical complications other than their skeletal changes.

Type II: Hunter-Thompson Type (Amdh)

The prevalence is unknown but it seems to be less frequent than the other types of acromesomelic dysplasia. Dwarfism is present at birth. The adult height is approximately 120 cm. The trunk is normally proportioned. Severe dwarfism is mostly limited to the limbs (extremely short stature), with the legs more severely affected than the arms. The middle segment (forearm with bowing of the radius and posterior dislocation of its head; lower leg with marked shortening of tibia and fibula) and distal segment (short hands and feet) show the most severe changes. Dislocation of the large joints (elbow, hip, knee, ankle) is frequently observed. The fingers usually are very short secondary to cuboidal shape of the metacarpals and shortening of the middle and proximal phalanges. Intelligence, facial appearance, and head circumference are normal. Corneal opacities may occur.

Type III: Grebe Type (Amdg)

Short-limbed dwarfism affecting both sexes and evident from birth. The most characteristic features are extremely short limbs, with the legs more severely affected than the upper limbs. The hands are extremely short with toe-like fingers, and the feet are in valgus position. Polydactyly is present in 50% of patients. Facies is normal and obesity is common. Mental development is delayed, but patients ultimately are mentally normal.

Type IV: Brahimi Bacha Type

Spondylometaphyseal dysplasia, most often associated with severe metaphyseal changes and severe genua valgum.

Type V: Campailla Martinelli Type

Dwarfism with severe limb shortening, most pronounced in the forearms and lower legs, associated with dysplasia of the tubular bones of the hands and feet. Intelligence is normal.

Normal craniofacial and axial skeleton. Care with positioning of the limbs because of high risk for dislocations. No specific anesthetic considerations.