Author/Editor		Djian, Philippe; Hancock, John M.; Chana, Harjinder S.
Title		Codon repeats in genes associated with human diseases
Type		članek
Vol. and No.		Letnik 93, št. 1
Publication year		1996
Volume		str. 417-421
ISSN		0027-8424 - Proceedings of the National Academy of Sciences of the United States of America
Language		eng
Abstract		Five human diseases are due to an excessive number of CAG repeats in the coding regions of five different genes. We have analyzed the repeat regions in four of these genes from nonhuman primates, which are not known to suffer from the diseases. These primates have CAG repeats at the same sites as in human alleles, and there is similar polymorphism of repeat number, but this number is smaller than in the human genes. In some of the genes, the segment of poly(CAG) has expanded in nonhuman primates, but the process has advanced further in the human lineage than in other primate lineages, thereby predisposing to diseases of CAG reiteration. Adjacent to stretches of homogeneous present-day codon repeats, previously existing codons of the same kind have undergone nucleotide substitutions with high frequency. Where these lead to amino acid substitutions, the effect will be to reduce the length of the original homopolymeric stretch in the protein.
Keywords		human diseases codon repeats in genes mutations človeške bolezni ponovitve kodona v genih mutacije