uniparental disomy

Wendy Robinson wendy at medgen.unizh.ch
Fri Jan 28 11:28:33 EST 1994

M. William Lensch (Lensch at chop.edu) wrote:
: Does anyone have any statistics on uniparental disomy? Which chromosomes
: have been noted as being involved other than chr. 15? What conditions does
: this cause other than those associated w/ chr. 15? I don't have e-mail so
: post here please. Thanks............

Updates concerning which chromsomes UPD has been observed for is published by
the 'committee for clinical disorders, chromosome abnormalities 
and uniparental disomy' as part of the Human Gene Mapping Workshops that are 
published by Cytogenetics and Cell Genetics.

Statistics: Ch15 maternal UPD occurs at a frequency of roughly 1/100,000.
Ch15 paternal UPD is much less frequently (roughly 1/500,000). No statistics
exist for any other chromosome.

Which chromosomes: 
Mat UPD has been observed for chromosome 4, 7, 9,13, 14, 15, 16, 21, 22.
Pat UPD has been observed for chromosomes 6,10, 14, 16, 21, X, XY.

Abnormal phenotype (besides homozygosity for recessive alleles:
Ch7 mat UPD -- short stature (e.g. Spotila et al. AJHG 1992 51:1396-1405).
Ch14 mat and pat UPD various findings including mild mental retardation
 (e.g. Antonarakis AJHG 52:1145-1152).
Ch15 mat UPD (Prader-Willi syndrome) pat UPD (Angelman syndrome).
Ch11 UPD(pat) is associated with Wilms Tumor and Beckwith-Wiedemann
syndrome. However this is segemental and seems to only exist as a post-
fertilization event. (see Henry et al. Eur. J Hum Genet 1:19-29).

For most other chromosomes there is either no imprinting effect, or the effect
of the UPD is obscured by presence of trisomic cell lines or recessive 
conditions. Chromosome 15 is the only UPD for which a clearly identifiable
syndrome is associated with UPD.

Wendy Robinson
Univ. of ZŸŸurich
Dept. of Medical Genetics
wendy at medgen.unizh.ch

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