A novel form of {open_quotes}Tyrosinase-positive{close_quotes} oculocutaneous albinism
Journal Article
·
· American Journal of Human Genetics
OSTI ID:134207
- Univ. of Wisconsin, Madison, WI (United States)
Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is greatly reduced in the skin, hair, and eyes. We have shown that typical ty-pos OCA (OCA2) results from mutations of the P gene in chromosome segment 15q11-q13. We have also shown that some patients diagnosed with ty-pos OCA actually have mild forms of type I OCA (OCAI), resulting from mutations at the tyrosinase (TYR) gene at 11q14-q21. However, in about one-third of patients with ty-pos OCA we have failed to identify abnormalities of either the P or TYR genes, suggesting the possible existence of a third ty-pos OCA locus. To test this hypothesis, we investigated a large, complex, inbred Pakistani kindred. Affected individuals exhibit slight skin pigmentation with no tanning, hair that is silver at birth and darkens somewhat over time, brown irides, and reduced visual acuity with nystagmus. SSCP/heteroduplex screening and complete DNA sequence analysis of TYR gene in the proband identified no abnormalities, and analysis of a CA repeat in the TYR gene promoter showed no linkage of ty-pos OCA to this marker in this kindred. SSCP/ heteroduplex screening of the P gene also detected no abnormalities, and the (inbred) proband was heterozygous for numerous intragenic polymorphisms. These data thus exclude TYP and P. We next carried out genetic linkage analyses and homozygisty mapping using various SSLP repeats at the locations of the human homologues of the mouse brown (TYRP, 9p23), slaty (13q32), and silver (12pter-q21) genes, all of which are associated with generalized hypopigmentation in mutant animals. However, we found no evidence of linkage of any of these markers. We are currently carrying out similar analyses using markers near the putative locations of the human homologues of several other mouse hypopigmentation genes in an effort to map this novel human ty-pos OCA locus.
- OSTI ID:
- 134207
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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Identification of a mutation in the tyrosinase related protein 1 (TRP1) gene associated with brown oculocutaneous albinism (OCA3)
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Thu Sep 01 00:00:00 EDT 1994
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OSTI ID:134067
The tyrosinase-positive oculocutaneous albinism gene shows locus homogeneity on chromosome 15q11-q13 and evidence of multiple mutations in southern African negroids
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Wed Jun 01 00:00:00 EDT 1994
· American Journal of Human Genetics; (United States)
·
OSTI ID:7200374
Identification of a mutation in the tyrosinase related protein 1 (TRP1) gene associated with brown oculocutaneous albinism (OCA3)
Journal Article
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Thu Sep 01 00:00:00 EDT 1994
· American Journal of Human Genetics
·
OSTI ID:133284