medwireNews: Researchers confirm that pubertal timing in girls is most strongly influenced by that of their mothers, whereas for boys their fathers have the stronger influence.
And the team supports their clinical findings with a genetic analysis suggesting that some genetic variants have stronger or weaker effects on male versus female pubertal timing.
Alexander Busch (University of Copenhagen, Denmark) and co-researchers studied data from 821 girls and 560 boys in the COPENHAGEN Puberty Study. They found that maternal pubertal timing (early, average or late) was significantly associated with all measures of girls’ pubertal timing, and paternal pubertal timing was associated with all measures of boys’ timing.
But for discordant sexes the results were mixed. Maternal pubertal timing was significantly associated with timing of testicular enlargement, pubic hair and voice break in boys, but not with sweat odour, axillary hair or testosterone above 0.23 nmol/L.
And paternal pubertal timing was associated with timing of pubic hair and menarche in girls, but not with thelarche, axillary hair or luteinizing hormone levels above 0.3 IU/L.
Mothers’ self-reported age at menarche was significantly associated with all pubertal milestones in daughters apart from axillary hair and in sons apart from sweat odour.
“Mirroring these clinical observations, large-scale genetic data underlines […] an overlapping genetic architecture between males and females but also highlights distinct loci exhibiting significant genetic heterogeneity between sexes”, write the researchers in the European Journal of Endocrinology.
Using genetic data from the UK Biobank study, they found 434 single nucleotide polymorphisms (SNPs) that were significantly associated with the timing of one or more of menarche, voice-break or facial hair.
The majority of these had a similar amount of influence over all three outcomes, supported by moderate genetic correlations even between the male and female pubertal timings, at a correlation coefficient of 0.55 for facial hair and menarche, and of 0.70 for voice-break and menarche (where 1.0 is perfect correlation).
But 35 of the SNPs showed significant heterogeneity on the basis of sex; in other words, they were more strongly associated with menarche than with the two male outcomes (or vice versa) but had similar strengths of association with facial hair and voice-break.
A further four SNPs showed significant heterogeneity between all three outcomes, supporting the imperfect genetic correlation between voice-break and facial hair, with a correlation coefficient of 0.86.
“Notably, none of the SNPs that exhibited significant genetic heterogeneity [were] located on the X chromosome”, say Busch and team.
By Eleanor McDermid
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