Evidence for variable gene expression in a large inbred kindred with autosomal recessive spondylocostal dysostosis

Seven members of a large inbred kindred with autosomal recessive spondylocostal dysostosis were examined clinically, radiographically, and sonographically. The subjects were three adults, one adolescent, and three children under 3 years of age. One child was the offspring of a first cousin marriage which showed quasi-dominant inheritance. Six subjects had short stature owing to widespread vertebral dyssegmentation with variable reduction in rib number and rib fusion. One subject was of normal stature, had limited vertebral dyssegmentation, an extra rib, and no rib fusion. Five subjects showed the plagiocephaly-torticollis sequence. Four of the five male subjects had inguinal herniation on one or both sides. All subjects had normal renal ultrasonography. The youngest subject died of cardiopulmonary complications and is thought to represent one extreme in the expressivity of the gene in this kindred.