AR

[dopey]

Baldness and the androgen receptor: the AR polyglycine repeat polymorphism does not confer susceptibility to androgenetic alopecia.
Ellis JA, Scurrah KJ, Cobb JE, Zaloumis SG, Duncan AE, Harrap SB
Hum Genet. 2007 May ; 121(3-4): 451-7

Androgenetic alopecia, or male pattern baldness, is a complex condition with a strong heritable component. In 2001, we published the first significant evidence of a genetic association between baldness and a synonymous coding SNP (rs6152) in the androgen receptor gene, AR. Recently, this finding was replicated in three independent studies, confirming an important role for AR in the baldness phenotype. In one such replication study, it was claimed that the causative variant underlying the association was likely to be the polyglycine (GGN) repeat polymorphism, one of two apparently functional triplet repeat polymorphisms located in the exon 1 transactivating domain of the gene. Here, we extend our original association finding and present comprehensive evidence from approximately 1,200 fathers and sons drawn from 703 families of the Victorian Family Heart Study, a general population Caucasian cohort, that neither exon 1 triplet repeat polymorphism is causative in this condition. Seventy-eight percent of fathers (531/683) and 30% of sons (157/520) were affected to some degree with Androgenetic Alopecia. We utilised statistical methods appropriate for the categorical nature of the phenotype and familial structure of the cohort, and determined that whilst SNP rs6152 was strongly associated with baldness (P < 0.0001), the GGN triplet repeat was not (P = 0.13). In the absence of any other known common functional coding variants, we argue that the causative variant is likely to be in the non-coding region, and yet to be identified. The identification of functional non-coding variants surrounding AR may have significance not only for baldness, but also for the many other complex conditions that have thus far been linked to AR.

 

[elguapo]

en ingles, por favor.

 

[michael barry]

extremely interesting.

I'd like to hear Doctor's opinions on this find and where it might lead to in research.

 

[hedgehog_info]

"The identification of functional non-coding variants surrounding AR may have significance not only for baldness, but also for the many other complex conditions that have thus far been linked to AR."

In English it means...

Parts of the DNA that are not part of the protein are probably the cause for male pattern baldness. Most likely some part of the DNA that controls the regulation of expression this protein and or regulation of how the protein get puts together.

Or you could also say they basically ruled something out ("GGN triplet repeat.") which will hopefully lead to new studies.

 

[docj077]

This study is very odd to me. I could have sworn that researchers had already established that the severity of the male pattern baldness that one is destined to deal with was directly determined by the number of triplet repeats in the gene encoding the androgen receptor itself. Now, they are saying that male pattern baldness is more closely related to a single nucleotide polymorphism within the gene? Plus, I read really fast, but they make it sound like the muation isn't even in the coding region. That really makes no sense to me in terms of the inheritability of the condition as this finding would completely alter any line of thinking that deals with male pattern baldness as a progressive disease throughout families.

I'd be more interested to see the study take the SNP mutation and the triplet repeat mutation population numbers and do an analysis with those two numbers to see how many men with male pattern baldness that have the SNP mutation also have the triplet repeat mutation. I'd like to know this information, because I'd like to know if the severity of the triplet repeat mutation correlates with the severity of one's tendency towards early onset male pattern baldness. A single gene polymorphism could alter function or even expression, but it shouldn't give us the diversity that we with male pattern baldness in terms of the patterning. The distribution of 5-alpha-reductase in the scalp simply has to be one of the major factors that influences that nature and the patterning that we all see.