rs314276 — LIN28B

Intronic variant in LIN28B associated with puberty timing — the C allele may be linked to earlier menarche in females and earlier puberty milestones in males, with implications for reproductive window length and cumulative estrogen exposure

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LIN28B rs314276 — An Independent Puberty Clock Signal

LIN28B encodes an RNA-binding protein that functions as a central regulator of developmental timing in mammals. By suppressing let-7 microRNAs11 let-7 microRNAs
A class of small non-coding RNAs that promote cellular differentiation and suppress growth signals; rising let-7 levels mark the transition from a growth-permissive to a maturation state, LIN28B activity holds the hypothalamic-pituitary-gonadal (HPG) axis in a pre-pubertal state. When LIN28B expression falls below a developmental threshold, let-7 levels rise and the GnRH pulse generator activates, initiating puberty. Common regulatory variants near LIN28B shift this threshold, making the pubertal transition arrive slightly earlier or later at the population level.

rs314276 is an intronic variant at chromosome 6q16.3 — the same LIN28B locus as rs7759938 (also studied in this platform), but in low linkage disequilibrium with it. Multiple studies examining both variants simultaneously have confirmed that they are partially independent signals within the LIN28B region, likely tagging distinct regulatory haplotypes that each modulate LIN28B expression to different degrees.

The Mechanism

rs314276 lies within an intron of LIN28B at GRCh38 position Chr6:104,960,124. The A and C alleles are on the plus strand; the C allele is the more common allele globally (~65% frequency) and is associated with somewhat earlier puberty timing. The variant most likely acts as a tag for a regulatory element that influences LIN28B expression in hypothalamic or pituitary tissue — the precise causal variant has not been isolated at this locus. As with rs7759938, the functional consequence is quantitative and probabilistic, shifting the population distribution of puberty onset rather than deterministically controlling it. Each C allele may shift the average age at menarche approximately 1–2 months earlier.

The Evidence

Ong et al. (2009)22 Ong et al. (2009)
Nature Genetics; 4,714 discovery + 16,373 replication women was the primary discovery paper for rs314276. In the GWA stage, each C allele was associated with 0.22 years (95% CI: 0.14–0.29) earlier menarche; in the larger replication stage the estimate converged to 0.12 years (95% CI: 0.08–0.16; p=3.6×10⁻¹⁶ combined), consistent with the winner's curse phenomenon. Effects on male pubertal milestones were also demonstrated: earlier voice breaking (p=0.006; n=1,026) and more advanced pubic hair development (p=0.01; n=4,588). Girls with earlier LIN28B-driven puberty also showed higher BMI during the mid-childhood and adolescent growth period.

In a longitudinal UK cohort of 2,451 individuals followed from ages 2–53 years, Ong et al. (2011)33 Ong et al. (2011)
JCEM; MRC National Survey of Health and Development found the C allele at rs314276 was associated with higher BMI specifically in women from ages 15–43, with the effect peaking around age 26 and then declining. No association was found with adult obesity or with BMI in men, consistent with a transient, puberty-mediated adiposity shift rather than a long-term metabolic risk.

In Taiwanese girls, Chen YC et al. (2017)44 Chen YC et al. (2017)
JPEM; 116 CPP cases, 102 controls found CC homozygotes at rs314276 were significantly more common in central precocious puberty cases. This aligns with the mechanism: higher C allele dosage may associate with greater LIN28B regulatory activity at this tag SNP, advancing the HPG axis earlier into the precocious puberty range for some individuals.

A smaller study of 248 Greek girls Tsinopoulou et al. (2024)55 Tsinopoulou et al. (2024)
Children; n=248 found no significant association in that cohort, likely reflecting inadequate power to detect the modest per-allele effect (~1–2 months) in a small population. This does not contradict the larger replicated studies.

Practical Implications

The per-allele effect of rs314276 on menarche (~1–2 months per C allele) is modest at the individual level, but the biological framing matters: two C alleles places a person in the earlier-maturing portion of the LIN28B locus haplotype space. When combined with rs7759938 status, the combined picture of LIN28B regulatory variation may be more informative than either SNP alone. Earlier menarche carries implications for total lifetime estrogen exposure, uterine fibroid risk, and reproductive planning context — as documented in the broader LIN28B literature.

For females, the key action-relevant insight for CC carriers is that cumulative estrogen exposure begins somewhat earlier, which is associated (at the population level) with moderately elevated uterine fibroid risk over the lifespan. For males, the variant may contribute to earlier pubertal milestones but has no specific actionable consequence in isolation.

The BMI finding from Ong et al. is worth noting for clinical context: CC carriers may tend toward higher BMI during adolescence and young adulthood due to the earlier and faster growth tempo, not due to metabolic dysfunction. This typically normalizes in adulthood.

Interactions

rs7759938 (LIN28B): rs314276 and rs7759938 are at the same LIN28B locus but are in low linkage disequilibrium with each other. Multiple population studies (Russian and Greek cohorts examining both variants simultaneously) describe the overall LIN28B LD structure as showing low pairwise r² across the four main tag SNPs in this region. rs7759938 was the lead SNP in the Perry et al. (2009) GWAS; rs314276 was the lead in the concurrent Ong et al. (2009) GWAS. They tag partially distinct haplotype effects. Individuals who are CC at rs314276 and TT at rs7759938 may carry the strongest combination of LIN28B puberty-advancing haplotypes at this locus — a compound action is proposed for the supervisor.

rs314280 (LIN28B): A third LIN28B tag SNP also studied in the menarche literature. Together with rs314276 and rs7759938, these three variants define the main haplotype diversity at the LIN28B locus for puberty-timing research.

PCOS-related variants: As demonstrated in the Carroll et al. (2012) PCOS data for rs7759938, LIN28B puberty-advancing alleles show amplified effects on menarche timing in hyperandrogenic contexts. This may also apply to rs314276 CC homozygotes with concurrent PCOS-pathway variants, though direct data are not available for rs314276 specifically in PCOS populations.

Genotype Interpretations

What each possible genotype means for this variant.

AA Later Timing Normal

No puberty-advancing C alleles at rs314276 — puberty timing tends toward the average or later end of the population range

The AA genotype at rs314276 is the low-frequency protective end of the additive distribution at this locus. With a global C allele frequency around 65%, AA homozygotes represent the approximately 12% who inherited the A allele from both parents. In population studies, AA individuals would be expected to have the latest average menarche of the three genotype groups at this locus, by approximately 2–4 months compared to CC homozygotes.

For males, no specific actionable implication has been identified for the AA genotype at this variant.

AC Intermediate Timing Intermediate

One puberty-advancing C allele — mildly earlier puberty timing

Under the additive model, AC heterozygotes fall approximately midway between AA and CC homozygotes. The Ong et al. (2009) replication estimate of 0.12 years per C allele means AC carriers are expected to have menarche roughly 0.12 years (about 1.5 months) earlier than AA carriers on average. The discovery stage estimate was 0.22 years per allele, but the true effect is likely closer to the replication-corrected estimate due to winner's curse inflation.

The longitudinal BMI data from Ong et al. (2011) suggest that AC carriers in females may trend toward slightly higher BMI during adolescence compared to AA carriers, with the effect most noticeable between ages 15–43 before attenuating in later adulthood.

CC Earlier Timing High Risk

Two puberty-advancing C alleles — earlier menarche and puberty timing, with implications for estrogen exposure window and uterine health

The CC genotype at rs314276 carries the maximum per-SNP effect from this LIN28B tag variant. The evidence for the association is well-replicated: the original Ong et al. (2009) GWAS (combined p=3.6×10⁻¹⁶ in 21,087 women) established this as one of the most significant common variants for menarche timing at the time of discovery. Subsequent studies in Taiwanese, Greek, and Russian populations all examine this variant as a key LIN28B tag SNP.

The BMI data from Ong et al. (2011) are particularly relevant for CC females: the C allele was associated with elevated BMI specifically from ages 15–43 in women (peaking around age 26), with no effect on adult obesity. This pattern reflects the earlier and faster adolescent growth tempo, not a metabolic disorder. CC females may have tended to be heavier during adolescence and early adulthood compared to AA carriers, typically normalizing by middle age.

The CPP association from Chen YC et al. (2017) indicates that among girls who experience medically defined precocious puberty (before age 8), CC homozygosity at rs314276 is over-represented. This does not mean CC guarantees early puberty, but rather that the variant is one contributing factor to the population distribution of very early puberty onset.

Within the LIN28B locus, multiple regulatory tag SNPs have been independently associated with menarche timing in different GWAS. CC homozygosity at this position represents the maximum effect from this particular tag SNP, and the rationale for proactive monitoring is correspondingly stronger.