Differential diagnosis The physical manifestations of Klinefelter syndrome are often variable. Kremer, J. Referral to molecular analysis of complementation groups, or targeted exome sequencing is also recommended for abnormal results. Recommended practice for laboratory reporting of non-invasive prenatal testing of trisomies 13, 18 and a consensus opinion.
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A disease can arise as a result of a balanced rearrangement if the breaks in the chromosomes occur in a gene, resulting in an absent or nonfunctional protein, or if the fusion of chromosomal segments results in a hybrid of two genes, producing a new protein product whose function is damaging to the cell.
Back up cultures of prenatal samples should be kept until the final report is written, and when practicable, the possibility of freezing viable cells, as well as fixed cell pellets should be available for cases that may require further cytogenomic or molecular analysis.
Growth and body proportions in 53 boys and men with Klinefelter's syndrome. Our results showed that large and submicroscopic Yq deletions were associated with significantly increased percentages of 45,XO cells in lymphocytes and of sperm cells nullisomic for gonosomes, especially for the Y chromosome.
In fluorescent in situ hybridisation FISH. Arch Dis Child.
Unbalanced rearrangements include deletions, duplications, or insertions of a chromosomal segment. Males with 46,XX typically have normal external genital development, but hypospadia or cryptochidism may be seen [ 29 ]. Lancet, — All Genetic Alliance content, except where otherwise noted, is licensed under a Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
It also should be noted that methylation status may vary across tissues e.
Where a deletion or a rearrangement is suspected, adequate hybridisation efficiency can be confirmed either by the presence of a signal on the normal chromosome or if a control probe is provided in the probe mix. Hum Reprod. Interphase FISH could be used as a method of choice in instances where rapid test results are required, for example, to detect trisomy 21 or sex chromosome constitution in newborns.
Lazebnik, N. Chronically Unfeasible. European guidelines for constitutional cytogenomic analysis.