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GEN News Highlights : May 18, 2009

SNPs Found to Determine the Age at Which Girls Experience Menarche

Variations on chromosome 6q21 are associated with AAM one to two months later per copy carried, says Nature Genetics study.

Scientists from deCODE genetics have found specific genetic factors that influence the age at menarche (AAM) of girls, which not only marks the beginning of a woman’s reproductive life, but also is linked with susceptibility to disease later in life. Earlier AAM is linked to obesity, and associated with risk of breast, ovarian, and endometrial cancers. Later AAM increases risk of osteporosis.

In the paper titled “Genome-wide association study identifies sequence variants on 6q21 associated with age at menarche” published May 17 in the online edition of Nature Genetics, the researchers identified two SNPs on chromosome 6q21 that are associated with between one and two months later AAM per copy carried.

Last year the investigators linked the same SNPs to greater adult height, and increased adult height has been shown to correlate with later AAM. An analysis of height measurements from 38,000 Icelandic women indicated that those carrying these SNPs were 0.3 cm taller per copy carried.

AAM appears to affect height, and not the other way around. 6q21 variants also confer greater adult height in men, and this  suggests that these SNPs should be involved in the onset of puberty in boys as well. The deCODE team also demonstrated that several known genetic variants linked to being overweight and obese also correlate with earlier AAM.