Y-specific polymerase chain reaction for the interpretation of a chromosome marker.

Chromosome marker is a very special type of chromosomal aberration. In addition to their normal chromosomes, patients with this type of disease own one (or more) small, unrecognizable chromosome. The extra chromosome markers may originate from the products of breakage and translocation of other chromosomes. Interpretation of the chromosome marker is usually very difficult, but its presence is an important prognosis factor for patients if the marker originated from a Y chromosome, or its components. This study explores the possibility of interpreting the chromosome marker by Y-specific polymerase chain reaction. A pair of primers designed from one Y-specific DNA sequence was employed. By studying normal controls, the most specific conditions for the chain reaction were established. Comparison of normal males and females showed that this reaction is specific to males (that is, to the Y chromosome). Also one patient with a karyotype 46,X,+marker was studied. The external genitalia of this patient were female type except for an enlarged clitoris. Y-specific polymerase chain reaction showed that the patient did have the Y-specific sequence. The chromosome marker did originate from the Y chromosome. This work proposes that Y-specific polymerase chain reaction is an effective and necessary diagnostic procedure for patients with chromosome marker.