Correlation of 2D:4D digit ratio and craniofacial shape in prepubertal children
Kalliopy Valla1, Demetrios J Halazonetis
1Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Greece.
Insights
The 2D:4D digit ratio did not correlate with craniofacial shape in prepubertal children. This study suggests prenatal hormone proxies may not influence normal craniofacial development during childhood.
Area of Science:
- Anthropology
- Genetics
- Pediatrics
Background:
- The 2D:4D digit ratio, a marker for prenatal androgen exposure, is sexually dimorphic.
- Recent research links the 2D:4D ratio to genes involved in ocular and palate development.
- Investigating the 2D:4D ratio's association with craniofacial morphology offers insights into developmental biology.
Purpose of the Study:
- To examine the correlation between the 2D:4D digit ratio and craniofacial skeletal shape in prepubertal children.
- To determine if digit ratios predict craniofacial morphology in a pediatric population.
- To explore potential links between prenatal hormone proxies and skeletal development.
Main Methods:
- A cross-sectional study of 117 prepubertal children (7-12 years) including 58 males and 59 females.
- Craniofacial shape analysis using 15 landmarks on lateral cephalometric radiographs.
- Digit ratio measurement via a computer-assisted procedure, with geometric morphometric and multivariate regression analyses.
Main Results:
- No statistically significant sexual dimorphism was observed in the 2D:4D ratio between male and female prepubertal children.
- Craniofacial shape did not exhibit sexual dimorphism, although males were larger overall.
- No significant correlation was found between the 2D:4D digit ratio and craniofacial shape in the entire sample or within sex-specific groups.
Conclusions:
- The 2D:4D ratio, a proxy for fetal sex hormones, may not exert a measurable influence on craniofacial shape variation in healthy prepubertal children.
- Multiple factors likely contribute to the development of both craniofacial structures and digits.
- Future research should investigate adult samples to assess potential covariation after the pubertal growth spurt.
Objectives:
The 2D:4D ratio is sexually dimorphic and is considered a proxy of prenatal androgen levels, or, according to recent evidence, is related to genes involved in ocular and palate development. Our aim was to investigate correlation between the 2D:4D ratio and the shape of the craniofacial skeleton in a population of prepubertal children.
Methods:
We conducted a cross-sectional study in a group of 58 male and 59 female prepubertal children aged 7-12 years. Craniofacial shape was evaluated using 15 skeletal landmarks on lateral cephalometric radiographs and fingers were measured with a computer-assisted procedure that involved tracing the finger outline. Geometric morphometric analysis was applied to the craniofacial landmarks and multivariate regression between digit ratios and craniofacial shape was computed in shape space and form space.
Results:
The male 2D:4D ratio was smaller than the female ratio (Cohen's d: 0.275 left hand, 0.126 right hand), but the difference was not statistically significant. Craniofacial shape did not show sexual dimorphism, but males were larger than females. No correlation was found between digit ratio and craniofacial shape in prepubertal children, either for the whole sample or for any of the two sex groups.
Conclusions:
As several factors might be involved in the development and growth of both the craniofacial complex and fingers, the 2D:4D ratio, a putative proxy for fetal sex-hormone levels, is probably unable to impose a measurable effect within the variation of a normal population. Future research needs to examine an adult sample for potential covariation arising after the pubertal growth spurt.
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