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Published on: April 22, 2015
The ratio of 2nd and 4th digit length in autistic children
1Department of Pediatrics, Bangkok Metropolitan Administration Medical College and Vajira Hospital, Bangkok, Thailand.
Insights
Lower 2D:4D ratios in both hands were observed in autistic children compared to non-autistic children. These digit ratios between 0.96 and 1.01 indicate an increased risk factor for autism in children.
Area of Science:
- Developmental Pediatrics
- Autism Spectrum Disorder Research
- Human Embryology and Endocrinology
Background:
- Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition with multifactorial etiology.
- Prenatal hormone exposure, particularly androgens, is hypothesized to influence neurodevelopment and is indirectly assessed via 2D:4D digit ratios.
- Understanding potential biomarkers and risk factors for ASD is crucial for early identification and intervention.
Purpose of the Study:
- To investigate the association between the second digit to fourth digit (2D:4D) ratio and the risk of autism in children.
- To compare 2D:4D ratios between autistic children and typically developing controls.
Main Methods:
- A hospital-based case-control study involving children aged 18 months to 15 years.
- Demographic data and autism risk factors were collected via questionnaires.
- Finger lengths (2nd and 4th digits) were measured using an electronic digital caliper to calculate the 2D:4D ratio.
Main Results:
- Autistic children exhibited significantly lower 2D:4D ratios on both the right (0.99 ± 0.06) and left hands (0.99 ± 0.07) compared to non-autistic children (right: 1.02 ± 0.04, left: 1.01 ± 0.03).
- A 2D:4D ratio between 0.96 and 1.01 for both hands was identified as a risk factor for autism.
- This specific digit ratio range was associated with an increased odds of autism, ranging from 3.22 to 5.35 (p < 0.05).
Conclusions:
- Lower 2D:4D ratios in both hands are associated with autism in children.
- The 2D:4D digit ratio within the range of 0.96 to 1.01 serves as a potential indicator for increased autism risk in children aged 18 months to 15 years.
- These findings suggest that prenatal hormonal influences, reflected by digit ratios, may play a role in the development of autism.
Objective:
To compare 2D:4D ratios of autistic to non-autistic children as a risk factor of autism.
Material And Method:
A hospital based case-control study was conducted from March 2007 to July 2008. Demographic data and general risk factors of autism had been collected using questionnaires from case and age matched control subjects aged 18 months to 15 years. Length of 2nd and 4th digits was measured by an electronic digital caliper.
Results:
The ratio of right hand 2D:4D of autistic children was 0.99 +/- 0.06 compared with 1.02 +/- 0.04 of non-autistic children (p = 0.01). On the other hand, 2D:4D ratio of left hand of autistic children was 0.99 +/- 0.07 while the ratio of non-autistic children was 1.01 +/- 0.03 (p = 0.04). The 2D:4D ratio of both hands between 0.96 and 1.01 were risk factors of autism with odds ratio between 3.22 and 5.35 (p < 0.05).
Conclusion:
The ratios of 2D:4D of both hands of autistic children were lower [corrected] than non-autistic children. The ratios of 2D:4D between 0.96 and 1.01 of both hands associated with an increased risk of autism in children aged 18 months to 15 years.
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