The SC phocomelia syndrome: report of two cases with cytogenetic abnormality.

We report two sibs with the SC phocomelia syndrome with typical facial appearance and bilateral absence or extreme hypoplasia of the fibula, radius, and thumb. One sib had bilateral humero-ulnar and femoro-tibial synostosis (absence of the elbow and knee joints). Application of the nosologic criteria of Herrmann and Opitz showed that there was no significant intrafamilial variation in phenotype. Chromosome analyses in both patients showed heterochromatic puffing and centromere separation involving many chromosomes, an observation that has previously been reported in patients with SC phocomelia and Roberts syndromes. More important, this finding will have significance in prenatal detection of a certain proportion of cases with these syndromes without resorting to the use of radiographic examinations.