Acromicric Dysplasia

Disease characterized by severe growth retardation, mild facial anomalies, and markedly shortened hands and feet secondary to short and stubby metacarpals and phalanges.

Approximately 30 cases have been reported. Most cases seem to be sporadic; however, vertical transmission also has been described, Because both sexes are affected, an autosomal dominant mode of inheritance is most likely. Acromicric dysplasia, geleophysic dysplasia, and Moore-Federmann syndrome may be allelic forms of the same disorder of different disturbances of the same metabolic pathway.

Histologic, histochemical, and electron microscopic examinations of the growth cartilage reveal lesions having disorganization of the growth zone with islands of cells, some showing signs of degeneration. Abnormal organization of collagen results in thick rims surrounding the cells and wide fibers in the interterritorial matrix. Most chondrocytes contain large accumulations of glycogen.

Based on the clinical features. Radiologic examination reveals short stubby metacarpals and phalanges with notching of the second metacarpal on the radial side and the fifth metacarpal on the ulnar side. The shapes of the epiphysis and metaphysis of the long bones are almost normal, except for a slight deformation of the femoral heads in some patients.

Mild facial anomalies, marked shortening of hands and feet, and growth retardation, which is severe in the majority of patients. Body length at birth is usually normal, but short stature becomes progressively evident with increasing age and reaches a final body height of approximate 130 cm. Mild dysmorphic features that are present at birth most often disappear later in life. Intelligence usually is normal. Joint mobility may be limited secondary to severe contractures. Other possible features include spine abnormalities, hoarse voice, and frequent infections of the ears and upper airway. Apart from short metacarpals and phalanges, a notch on the radial side of the second metacarpal, a notch on the ulnar side of the fifth metacarpal, and a notch along the internal border of the femoral heads, no other major radiographic abnormalities have been described. Storage phenomena (mucopolysaccharides), such as progressive thickening of the skin and mitral and aortic valves, and hepatomegaly have been described in a few patients. However, these storage phenomena seem to be more characteristic for Geleophysic Dysplasia and Moore-Federmann Syndrome.

Positioning may be difficult. Because of recurrent infections of the upper airway, careful preoperative examination should ensure that the patient's airway is optimized for the procedure. Chest radiograph may be required; if in doubt, echocardiography may help assess valvular and cardiac function.