Growth abnormalities in genetic syndromes.

The presence of a growth abnormality may be documented by determination of growth velocity, calculation of the upper segment/lower segment ratio or the AF/AT ratio, and measurement of head circumference. Important considerations in differential diagnosis of specific malformation syndromes are birth weight, limb and truck alterations, head size, physical features, and presence or absence of mental retardation. Additional clinical measurements, such as measurement of chest circumference and of finger and hand length, may be useful in selected cases. These data, combined with historical information, can indicate a specific diagnosis and facilitate the choice of confirmatory laboratory studies.