ACTN3: Athlete gene prevalence in North India.

Alpha actinin is an actin-binding protein involved in anchoring thin filaments of actin to the Z-line of myofibrils. Two structural isoforms of alpha-actinin (ACTN2 and ACTN3) are present in fast twitch (type 2) fibres of the skeletal muscle. ACTN3 gene has two alleles, R and X; the R allele is able to code for full length protein, while no functional protein results from the X allele due to a nonsense mutation (R577X) in exon 16 of ACTN3. The presence of X and R alleles of ACTN3 has been reported to affect the sprinting and endur ance abilities of elite athletes. Therefore, ACTN3 is also known as the 'althlete gene'. The frequencies of the two alleles show considerable variation in different populations of the world. The aim of the present study was to determine the status of R and X alleles of ACTN3 in North Indian population. Using PCR-RFLP, we found homozygous R in 27 (22%), heterozygous RX in 76 (61%) and homozygous X in 22 (17%) out of 125 healthy voluntary blood donors. The study revealed that frequencies of both alleles and genotypes of ACTN3 in North Indians are similar to those of Caucasian populations. [ABSTRACT FROM AUTHOR]