Chondrodysplasia Grebe Type

A rare form of autosomal recessive osteochondrodysplasia characterized by severe dwarfism with marked hypomelia and deformation.

Grebe Chondrodysplasia; Brazilian Achondrogenesis; Acromesomelic Dysplasia, Grebe Type; Acromesomelic Dwarfism; Achondrogenesis Type II.

Fewer than 100 cases have been described. An increased frequency has been reported from Bahia, Brazil, where the gene frequency was evaluated to be 1:50, with a prevalence of 1:2000 live births.

Autosomal recessive as a result of a mutation in the cartilage-derived morphogenetic protein-1 gene (CDMP1) located on 20q11.2.

Based on the clinical findings of severe dwarfism with marked hypomelia and deformation of upper and lower limbs, with a proximo-distal gradient of severity. Radiographs show shortening and deformation of the forearm and foreleg bones, fusion of carpal and tarsal bones, and absence of proximal and middle phalanges and several metacarpal and metatarsal bones.

This disorder is limited to the skeleton and results in short limbs with the arms longer than the legs. The abnormalities are more severe distally: the humeri and femora are short but normally shaped, whereas radius/ulna and tibia/fibula are short and deformed, the carpal and tarsal bones and phalanges are rudimentary, and the metacarpals, metatarsals, and patellae are hypoplastic or absent. The digits are consequently very short with a globular appearance connected with a soft-tissue bridge. Postaxial polydactyly and valgus deformity of hand and foot are common. The metatarsal, talus, cuneiform, and navicular bones may be fused. The axial skeleton is normal. An increased frequency of stillbirth and neonatal death has been reported. No mental retardation.

Routine preoperative assessment. Check joint mobility for intraoperative positioning.

Anesthesia in this condition has not been described. The features of the disease suggest that vascular access may be difficult, and careful intraoperative positioning is required. Regional anesthesia is not contraindicated but should be expected to be difficult to perform due to positioning problems.

There are no specific implications for this condition.

Acromesomelic Dysplasia Maroteaux Type: A very rare, autosomal recessive inherited disorder that seems to have its highest prevalence on the south Atlantic island of St. Helena (to which Napoleon was exiled in 1815). Dwarfism is severe and affects mainly the middle and distal parts of the limbs (progressive shortening of the tubular bones and bowing of radius and ulna) and the vertebrae (thoracic kyphosis).

Acromesomelic Dysplasia Hunter-Thompson Type: Extremely rare form of autosomal recessive inherited acromesomelic dysplasia characterized by severe dwarfism with the abnormalities limited to the limbs (more pronounced in the lower limbs). Multiple dislocations of the large joints with limited mobility are common. Patients are mentally normal. The same gene as in chondrodysplasia Grebe type is responsible for this disorder, although the mutation affects a different part of the gene. Intelligence seems to be normal in these patients, although the psychomotor milestones achieved may be delayed compared to the normal population.