Rapid detection of chromosomes X and Y aneuploidies by quantitative fluorescent PCR

Prenat Diagn. 1999 Dec;19(12):1099-103. doi: 10.1002/(sici)1097-0223(199912)19:12<1099::aid-pd709>3.0.co;2-2.


Quantitative fluorescent polymerase chain reaction (QF-PCR) assays and small tandem repeat (STR) markers have been successfully employed for the rapid detection of major numerical aneuploidies affecting human autosomes. So far, the analysis of chromosomes X and Y disorders has been hampered by the rarity of highly polymorphic markers which could distinguish normal female homozygous PCR patterns from those seen in patients with Turner's syndrome. A new marker (X22) of the X/Y chromosomes has been identified which maps in the Xq/Yq pseudoautosomal region PAR2; used together with the HPRT it allows the rapid diagnosis of numerical aneuploidies of the sex chromosomes. Blood samples from normal male and female subjects and from patients with X and Y chromosome disorders (45,X and 47, XXY) have been tested by QF-PCR with the X22 polymorphic pentanucleotide (12 alleles) together with the HPRT and P39 markers. The samples were also tested by multiplex QF-PCR with STRs specific for chromosomes 21,18,13 and amelogenin (AMXY). Tested by QF-PCR, all samples from normal females were heterozygous for either the X22 or the HPRT marker with fluorescent peak ratios near 1:1, thus allowing a correct, rapid diagnosis of their chromosome complement. Turner's patients (45,X) showed only one X22 and one HPRT fluorescent peak, thus documenting the presence of a single X chromosome. Turner's patients with mosaicism showed a major fluorescent peak for the X22 and HPRT markers and a minor peak revealing the presence of a second minor population of cells. Two 47, XXY cases could also be diagnosed. Multiplex analyses can be performed using simultaneously STR markers for chromosomes 21,18,13 X and Y. The diagnostic value of a third X-linked marker (P39) was also investigated. These results suggest that rapid diagnosis of major numerical anomalies of the X and Y chromosomes can be performed using QF-PCR with a new highly polymorphic X-linked marker, X22, which maps in the Xq/Yq pseudoautosomal region PAR 2. Multiplex QF-PCR tests-using the X22 STR in association with HPRT and, in rare cases, a third P39 marker-allow the rapid diagnosis of major aneuploidies affecting chromosomes 21, 18, 13, X and Y. The X22 marker can also be employed for the detection of fetal cells present in maternal peripheral blood or the endocervical canal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aneuploidy*
  • Case-Control Studies
  • Female
  • Fluorescence
  • Genetic Markers
  • Humans
  • Karyotyping
  • Male
  • Polymerase Chain Reaction
  • Predictive Value of Tests
  • Turner Syndrome / blood
  • Turner Syndrome / diagnosis*
  • Turner Syndrome / genetics
  • X Chromosome*
  • Y Chromosome*


  • Genetic Markers