Brachyolmia Type 2

Description

The term 'brachyolmia' was coined to designate a bone dysplasia characterized clinically by short trunk dwarfism and radiographically by generalized platyspondyly without significant long bone abnormalities. The Maroteaux type of brachyolmia is an autosomal recessive form in which there is rounding of the anterior and posterior vertebral borders, with less elongation on lateral view and less lateral extension on anteroposterior view than is seen in the Hobaek type of brachyolmia (271530). Maroteaux brachyolmia may also be associated with precocious calcification of the falx cerebri, and minor facial anomalies (summary by Shohat et al., 1989).

For a discussion of genetic heterogeneity of brachyolmia, see 271530.

Clinical Features

Shohat et al. (1989) reported 4 families with the Maroteaux type of brachyolmia, including 2 brothers whose Israeli parents were first cousins, suggesting autosomal recessive inheritance. Birth length was below normal in 1 patient, and in the other patients short stature was usually evident during the first 2 years of life. After age 2 years, growth curves were 4 to 5 standard deviations below the mean but parallel to the norm. The lower segment was measured in 2 patients and the upper/lower segment ratio was normal. Arm spans were measured in 3 children and found to be longer than corresponding heights in 2 patients. Psychomotor development was normal in all but 1 patient who had mild mental retardation. Other physical findings included wide-spaced nipples, clinodactyly, hypoplastic nails, pectus excavatum, and hyperlaxity of joints. Precocious ossification of the falx cerebri was seen in 1 patient. Metaphyseal irregularity as well as small epiphyses of the proximal femurs were noted in 1 child, but none of the other patients had radiologic changes in the long bones. Facial appearance was normal.

Inheritance

Consanguinity and occurrence in sibs support autosomal recessive inheritance of this disorder (Shohat et al., 1989).