Anisomastia

Anisomastia, or mammary asymmetry, is a common problem in developing adolescent girls. Stratakis et al. (2000) evaluated a 22-year-old female patient who had severe anisomastia (which had been repaired by surgery) associated with moderate to severe mental retardation, a stocky body habitus with mild obesity, dysmorphic facies (prominent, upslanting palpebral fissures, beaked nose, and a prominent philtrum), webbed neck, low hairline, and severe bilateral clinodactyly of the third, fourth, and fifth fingers with acral (but not large joint) flexion contractures. A peripheral blood high-resolution karyotype revealed additional chromosomal material within the long arm of chromosome 16. Densitometric analysis of amplified polymorphic sequence-tagged sites (STSs) mapping to 16q suggested that the duplication is defined by the noninvolved markers D16S419 (16q12-cen, 66 cM from 16p terminus) and D16S421 (16q13-q21, 84.4 cM), encompassing a maximum of 18.4 cM of genetic distance. The STS analysis showed that the duplication was on the maternally derived chromosome 16, resulting in 2 maternal (and 1 paternal) copies of that region of chromosome 16. The location was further confirmed by BACs that were obtained from a commercially available library, labeled, and used for FISH studies. The BACs containing STSs D16S408, D16S3137, and D16S3032 (markers that correspond to 16q13) showed 2 regions of hybridization, indicating that these sites were duplicated, whereas a BAC containing the STS D16S512 (which corresponds to 16q21-q22) revealed 1 hybridization signal per 16q, indicating that the corresponding region was not involved in the duplication. The distance between the probe signals suggested a tandem duplication.