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TRISOMY 6 MOSAICISM
Trisomy 6 is a rare prenatal finding. Trisomy 6 conceptions have not been observed in the large case reports of chromosomal mosaicism detected during chorionic villus sampling (Hahnemann & Vejerslev 1997).
Hsu (1997) reviewed three reported cases of trisomy 6 mosaicism found at amniocentesis. All three cases had 6% trisomy 6 cells and all were born with no health concerns.
Uniparental Disomy (UPD 6)
An imprinting effect is known for paternal UPD 6. DNA studies may be considered when prenatal diagnosis indicates trisomy 6 mosaicism. Paternal UPD is associated with neonatal diabetes mellitus (Ledbetter & Engel, 1995). Ledbetter and Engel (1995) summarized several cases of paternal UPD6 that have been reported.
Link to What is UPD?
Link to Maternal UPD 6 page
Link to Paternal UPD 6 page
Internet Links
HUGO Chromosome 6 - Chromosome 6 specific sites
Human Chromosome 6 - Provides links to gene maps, sequences, associated genetic disorders, nonhuman genetic models, identified genes, research efforts and laboratories, and other information as available. Links are very scientific.
References
Hahnemann JM, Vejerslev LO. (1997) European collaborative research on mosaicism in CVS (EUCROMIC)--fetal and extrafetal cell lineages in 192 gestations with CVS mosaicism involving single autosomal trisomy. American Journal of Medical Genetics 70(2):179-87. PubMed
Hsu LY, Yu MT, Neu RL, Van Dyke DL, Benn PA, Bradshaw CL, Shaffer LG, Higgins RR, Khodr GS, Morton CC, Wang H, Brothman AR, Chadwick D, Disteche CM, Jenkins LS, Kalousek DK, Pantzar TJ, Wyatt P. (1997) Rare trisomy mosaicism diagnosed in amniocytes, involving an autosome other than chromosomes 13, 18, 20, and 21: karyotype/phenotype correlations. Prenatal Diagnosis 17(3):201-42. PubMed
Ledbetter DH, Engel E. (1995) Uniparental disomy in humans: development of an imprinting map and its implications for prenatal diagnosis. Human Molecular Genetics 4:1757-1764 PubMed
Whiteford ML, Narendra A, White MP, Cooke A, Wilkinson AG, Robertson KJ, Tolmie JL. Paternal uniparental disomy for chromosome 6 causes transient neonatal diabetes. J Med Genet. 1997 Feb;34(2):167-8. PubMed |