Images in Clinical Practice

Indian Pediatrics 2002; 39:782-783

Metatropic Dystrophy

A 4 years old female child presented with the complaints of inability to walk and maintain a normal erect posture since early childhood. The child is the second product of a non-consanguineous marriage; the first child, a male, is normal. On examination, the height was 75 cm. The trunk was relatively short due to kyphoscoliosis and the limbs disproportionately long. The thorax was relatively narrow with a projecting sternum. The head and face was normal, head circumference being 47 cm. The knees and elbows appeared swollen. There was limitation of movements at the elbows, knees and ankles and a fixed flexion at the hips of about 120º. The metacarpophalangeal and interphalangeal joints were hyper-extensible. The hands and feet were stubby and a tail - like appendage due to an extra fold of skin was visible over the coccygeal region (Fig 1). Mental development was normal.

Fig. 1. Photograph showing the tail like appendage and kyphoscoliosis.

The x-rays revealed flaring of metaphyses of all the long bones with deformed, misshapen epiphyses. Pelvis was grossly deformed with curved iliac crests and anterior superior spines extending to the level of the highest point of the acetabulum which exhibited a notch above its lateral margin. Sacrosciatic notches were very narrow. Iliac bodies were hypoplastic and acetabular roofs horizontal (halbred appearance) (Fig. 2). Spine showed gross kyphoscoliosis with irregularity and variable flattening of the vertebrae and tongue-shaped protrusions on their anterior aspects. Cervical spine showed hypoplasia of the odontoid process. The metacarpals of the hands appeared relatively shorter than in infancy.

Fig. 2. X-ray of pelvis showing the hypoplastic iliac and the halberd appearances of acetabular roof.

In view of clinical and radiological features a diagnosis of metatropic dwarfism was made. Differential diagnoses include Morquio disease, Achondroplasia, Kniest disease and Kozlowski type of spondylometaphyseal dysplasia.

Metatropic Dwarfism is a rare condition whose exact incidence is not known. ‘Metatropic’ word indicates the change in body proportions that occurs in this condition. The disproportionately short-limbed infant develops kyphoscoliosis and ultimately a short-trunk type of dwarfism. Though many may die at a young age, the adult height ranges from 110-112 cm. The major life-threatening condition is due to respiratory failure. Progressive musculoskeletal deformities lead to gross disability.