rs4795541

This SNP represents a polymorphic region consisting of an "in/del", i.e. either an insertion or a deletion, of 43 or 44 nucleotides. This SNP is commonly known as the 5-HTTLPR variant of the serotonin transporter SLC6A4 gene. The deletion allele is referred to as the "S" allele, the insertion allele is known as the "L" allele, and hence the genotypes are usually called the LL, SL, and SS genotypes in publications. Note, however, that this is actually a tri-allelic SNP, in that on occasion, a single nucleotide, usually a G, may be present at this position. This SNP has been studied in many contexts, including the following: * Anxiety related behaviours and disorders * Depression ** Response to anti-depressant drugs * Seasonality and seasonal affective disorder * Suicide * Premature ejaculation ** Men with the LL genotype ejaculate about twice as quickly as men with SS or SL genotypes on average, based on a study of 89 Dutch men who suffer from the primary form of premature ejaculation. sciencedaily.com * Attention deficit disorder * Migraine * Bipolar mood disorder * Obsessive compulsive disorder * Fibromyalgia * Irritable bowel syndrome It is beyond the current scope to summarize all the associations seen for this SNP, as well as the lack of replication reported in some follow-on studies.