One of the two or more copies of each gene in an individual containing specific inheritable characteristics that occupy positions on paired chromosome. In people with VHL, one copy is altered and one has the normal sequence. Refers to the different forms of a gene at one locus. A, B and O are alleles for a blood group gene. A person with blood type AB has the A allele on one chromosome and the B allele at the same locus on the other homologous chromosome.
Different alleles produce variations in inherited characteristics such as eye color or blood type.
Alper Disease Progressive Infantile Poliodystrophy. A protein excreted by the fetus into the amniotic fluid and from there into the mother's bloodstream through the placenta. A disease that causes memory loss, personality changes, dementia and, ultimately, death. Not all cases are inherited, but genes have been found for familial forms of Alzheimer's disease. Ambiguous Uncertain or doubtful.