Anthropometry in skeletal dysplasia.

Skeletal dysplasia or osteochondrodysplasia is the designation of more than 200 different disorders, that are characterized by abnormalities of the skeleton, disproportional short stature, and a variety of other problems. The underlying biochemical defect is unknown in the vast majority of skeletal dysplasias, and the diagnosis is based on radiological findings and anthropometric measurements. Despite this fact, the information on body proportions in even the more common forms of skeletal dysplasia is scarce. Patients with achondroplasia are often diagnosed shortly after birth. Linear growth is severely compromised with relatively short extremities. Head circumference is above normal and final height ranges from 115 to 145 cm in males and 112 to 137 cm in females. Individuals with hypochondroplasia may go unnoticed until puberty, at which time the growth problem becomes obvious. Sitting height to height ratio is increased, but the body disproportion may not be apparent until puberty. Final height has been reported between 118 and 165 cm. Spondyloepiphyseal and spondylometaepiphyseal dysplasias are characterized by severe impairment of growth both in trunk and extremities, and therefore the sitting height to height ratio may be normal. Final height is severely reduced and ranges from 94 to 132 cm. It is concluded that anthropometric studies of patients with skeletal dysplasia are needed. More quantitative information on body proportions may assist in the diagnostic procedure and ensure that growth promoting therapy, e.g. growth hormone, does not worsen the disproportion.