Simultaneous genotyping of four functional loci of human SLC6A4, with a reappraisal of 5-HTTLPR and rs25531

5-HTTLPR Biases Amygdala Activity in Response to Masked Facial Expressions in Major Depression

“…We investigated 5-HTTLPR in combination with a recently discovered single nucleotide polymorphism (SNP) with an A-G substitution (rs25531). Since the S G allele seems to be a rare variant (Wendland et al, 2006; and was not found in the present sample at all) several previous reports treated 5-HTTLPR/rs25531 as a triallelic polymorphism. The L G allele was reported to behave comparable to the low expressing S allele (Hu et al, 2005).…”

“…All subjects were genotyped for the 5-HTTLPR polymorphism, including SNP rs25531 (A/G), according to published protocols (Deckert et al, 1997;Wendland et al, 2006) with minor variation. Primers 5 0 -GGCGTTGCCGCTCTGAATGC-3 0 and 5 0 -GAGGGACTGAGCTGGACAACCAC-3 0 (10 pM each) were used for 20 ml PCR containing 60 ng DNA, 200 mM dNTPs, H 2 O and 0.5 U HotStar Taq Polymerase with 1.5 mM MgCl 2 , 1 Â Q-Solution and 1 Â Buffer (Qiagen), with an initial 15 min denaturation step at 951C followed by 35 PCR cycles of 941C (60 s), 641C (60 s) and 721C (120 s) and a final extension step of 10 min at 721C.…”

The moderation by the serotonin transporter gene of environmental adversity in the aetiology of mental illness: review and methodological analysis

“…69,104 An adenosine/guanine (A/G) single-nucleotide polymorphism (SNP) located within the repeats of 5-HTTLPR seems to be relatively common even in Caucasian populations, with a minor (G) allele frequency (MAF) of 10%; it has been described as rs25531 SNP associated with either short or long 5-HTTLPR alleles 105 or as a L A /L G modifier of the long allele. 106 Wendland and colleagues 107 have demonstrated that the disagreement was caused by two alternative demarcations of the 5-HTTLPR insertion sequence and that the G/A rs25531 SNP can be associated with either l or s allele. It was reported, that in lymphoblastoid cell lines, the S and L G alleles were associated with lower 5-HTT expression compared to the L A allele.…”

“…Given that the rs25531 SNP can combine with either s or l allele, the two polymorphisms can be considered independently for analysis purposes. 107 The role of heterozygosity While most studies agree on the differential environmental effects on ss versus ll homozygotes, the findings in and reporting of effects in sl heterozygotes have been less consistent. Dominant, co-dominant and recessive models of the 5-HTTLPR s allele effect have all been proposed, but there is no clear consensus.…”

Functional SLITRK1 var321, varCDfs and SLC6A4 G56A variants and susceptibility to obsessive-compulsive disorder

“…Also of note, this same individual carried the very rare ( < 1%) S G allele of the SLC6A4 transcriptional control polymorphism, 5-HTTLPR. 9 As no further phenotypic information was available from the cell repository when we contacted them, we cannot evaluate nor rule out the possibility of subclinical neuropsychiatric symptomatology in this person.…”