Polytopic anomalies with agenesis of the lower vertebral column.

We describe clinical, pathological and radiological findings in 15 cases of sporadic and familial lower spine agenesis with additional anomalies of the axial skeleton and internal organs and speculate about the cause and pathogenesis of this malformation complex. We show that all of these findings are defects of blastogenesis, originate in the primary developmental field and/or the progenitor fields, thus representing polytopic field defects. This concept appears applicable in our cases and makes such terms such as "caudal regression syndrome" or "axial mesodermal dysplasia spectrum" redundant.

A further case of vertical transmission of proximal femoral focal deficiency?

We report on a newborn boy with congenital asymmetrically hypoplastic fibulae, lateral oligodactyly, and mild left ectrodactyly. The patient's grandfather had a short femoral shaft with a slightly smaller collodiaphyseal angle on the left as compared to the right side, probably a proximal focal femoral deficiency (PFFD). The upper limbs were not affected in either patient. PFFD in the grandfather and hypoplastic fibulae with lateral ray defects in the grandson raise the possibility of genetic transmission, specifically autosomal-dominant inheritance with variable penetrance and expressivity. This case gives further support to the fibular developmental field concept postulated by Lewin und Opitz [1986: Am J Med Genet (Suppl) 2:215-238].