To the Editor.—Caution is warranted in interpreting the causal role of extra centric chromosomal fragments in various congenital malformations.
Hoehn et al,1 in a review of 18 cases with morphologically similar minute extra chromosomes, described 25% as phenotypically normal, 50% as suffering from regular or translocated Down's syndrome, and the remaining clinically affected individuals as having, as the main common trait, mental retardation. Except for those cases with features suggestive of Down's syndrome, no particular phenotype-karyotype relationship could be established in cases with familial occurrence of an additional small centric chromosome.
We wish to report here a case of Prune-Belly syndrome in a family with an extra centric fragment. A newborn (birth weight 3,800 gm [8½ lb], born at term) was referred for cytogenetic studies because of the following congenital abnormalities: absence of abdominal wall muscles, polycystic kidneys, bilateral megaloureters, and genital hypoplasia.
Chromosome analysis of umbilical