ACHONDROPLASIA

 A 2 year old male child presented with features of retarded growth in the form of short height (height below 5th percentile). Altered upper to lower segment ratio and large head. However the child had normal intelligence.

 

 

Anchondroplasia is one of the oldest recorded growth disorders in ancient times. These individuals were kept as entertainers to the wealthy. Only since 19th century people with achondroplasia are known to be normal, except for their physical appearance.
It’s prevalence ranges from 0.36 to 0.6 per 10,000 live births.
Most obvious is their stature which averages approximately 50 inches. Characteristics can be recognized antenatally and at birth. Long bones are shortened, especially proximal ones (rhizomelic shortening). Cranium is large with prominent forehead and depressed nasal bridge. Base of skull is constricted with small foramen magnum which can lead to hydrocephalous ,cord compression and even sudden death.
The tubular bones of hands and feet are short and thick. The fingers are all of same length with separation of middle and ring fingers (trident hand). Ribs are quite short and donot extend around the thorax. Scapula may be squared inferiorly with a shallow glenoid.
Pelvis is small, ilia are shot and flat with small sciatic notches. Acetabular roof is horizontally oriented with thickening of the Y cartilage giving Champagne glass appearance of pelvis.
Symmetric shortening of all small bone with proximal bones being most affected. Flared bone ends with metaphyseal cupping is also seen.
In lumbar spine, there is progressive decrease in interpedicular distance caudally. Posterior scalloping of vertebral bodies and bullet nosed vertebrae may also be seen.
     

COMPLICATIONS:
Unexpected infant death and death risk (7.5%) due to respiratory dysfunction from brain stem compression at the cranio-cervical junction.
Other reported associations are chronic otitis media, conductive hearing loss, delayed speech, relative adenotonsillar hypertrophy, orthodontic problems, heart disease, spinal stenosis, jugular foramen and hypoglossal canal stenosis.