Genetic disorder with metaphyseal dysplasia that is more pronounced in the lower than in the upper extremities.
Metaphyseal Acrodysplasia; Metaphyseal Acroscyphodysplasia; Wedge-Shaped Epiphysis of Knees.
Only two Italian and two Australian siblings and two unrelated cases (one from Italy and one from Morocco) have been described.
Autosomal recessive inheritance was suggested.
The main clinical features of this metaphyseal chondrodysplasia are severe growth retardation, predominantly lower extremity micromelia, knee flexion contractures, and severe brachydactyly. The radiologic appearance of the knees is considered specific, with the distal femoral and the proximal tibial epiphyses embedding themselves in their corresponding metaphyses, which results in the typical cup shape on x-ray. The name acroscyphodysplasia refers to this characteristic cup-shaped (scyphus = cup) anomaly. Premature epiphyseal-metaphyseal fusion and gross deformation of the femoral condyles can occur. The distal femoral metaphyses appear wedge-shaped. The femoral diaphyses are short and broad. Additional features include progressive bilateral coxae valgae, bowed and/or short, stubby tibiae with cone-shaped metaphyses and varus deformity of the tibiotalar joint. Overall, the upper extremities are much less affected with only mild deformation of the long bones. However, the shortening of the hand and finger bones (brachydactyly, brachymesophalangy, cone-shaped phalangeal, and metacarpal epiphyses with irregular, bowed, and shortened diaphyses) can be significant. Similar changes are present in the feet. Mild scoliosis was noted in one patient. Psychomotor retardation is common, but normal intelligence has also been described. Described facial features include a thickened calvarium, bulging forehead, flat profile, hypertelorism, telecanthus, and broad nasal root with normal or small nose. Skin and hair are usually normal.
Precautions before anesthesia
Check for difficult airway management, however, despite the facial features, airway management is not expected to be difficult. Otherwise routine preoperative assessment is recommended. Developmental delay may cause agitation and stress in the perioperative period; thus, anxiolytic and sedative premedication and/or presence of a parent (or primary caregiver) for induction of anesthesia may be beneficial.
Positioning may be difficult and careful padding is required (osteopenia has been reported). No other defects have been described, thus no specific anesthetic implications are expected. Peripheral intravenous access may be challenging due to the short and stubby hands and feet. Ultrasound guidance will most likely be beneficial.
None specific to this disorder.
Other condition to be considered
Other types of ☞Metaphyseal Chondrodysplasia.
G: Wedge-shaped epiphyses of the knees in two siblings: A new recessive rare dysplasia? Helv Paediatr Acta