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Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders

BACKGROUND: The prevalence of autism spectrum disorders (ASDs) is higher in men than in women. The extreme male brain theory proposes that excessive prenatal testosterone activity could be a risk factor for ASDs. However, it is unclear whether prenatal sex hormone activity is a risk factor for women...

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Autores principales: Masuya, Yasuhiro, Okamoto, Yuko, Inohara, Keisuke, Matsumura, Yukiko, Fujioka, Toru, Wada, Yuji, Kosaka, Hirotaka
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4460687/
https://www.ncbi.nlm.nih.gov/pubmed/26060570
http://dx.doi.org/10.1186/s13229-015-0028-x
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author Masuya, Yasuhiro
Okamoto, Yuko
Inohara, Keisuke
Matsumura, Yukiko
Fujioka, Toru
Wada, Yuji
Kosaka, Hirotaka
author_facet Masuya, Yasuhiro
Okamoto, Yuko
Inohara, Keisuke
Matsumura, Yukiko
Fujioka, Toru
Wada, Yuji
Kosaka, Hirotaka
author_sort Masuya, Yasuhiro
collection PubMed
description BACKGROUND: The prevalence of autism spectrum disorders (ASDs) is higher in men than in women. The extreme male brain theory proposes that excessive prenatal testosterone activity could be a risk factor for ASDs. However, it is unclear whether prenatal sex hormone activity is a risk factor for women. The ratio of the length of the second to fourth digits (2D:4D) is considered to be a biomarker of the prenatal ratio of testosterone to estrogen. Therefore, this study compared the 2D:4D ratios of women with and without ASDs to determine if prenatal sex hormone activity could be a risk factor for ASDs in women. METHODS: The study included 35 Japanese men with ASDs, 17 Japanese women with ASDs, 59 typically developed (TD) Japanese men, and 57 TD Japanese women. We measured digit lengths and compared the 2D:4D ratios among the four groups. We also examined the relationship between the 2D:4D ratio and the autism-spectrum quotient score of each group. RESULTS: In our cohort, men with ASDs tended to have lower right-hand 2D:4D ratios relative to TD men. In contrast, the right 2D:4D ratios in women with ASDs were higher compared to those of TD women. No significant correlations were found between the 2D:4D ratios and the autism-spectrum quotient scores in any group. The higher right 2D:4D ratios in women could not be explained by age or full-scale intelligent quotients. This group difference was not found for the left 2D:4D or right–left 2D:4D ratios. CONCLUSIONS: We found a reverse direction of abnormality in the right 2D:4D ratio for men and women with ASDs. It has been posited that high prenatal testosterone levels lead to a lower 2D:4D ratio. However, a recent animal study showed that testosterone injection to dam leads to a higher right 2D:4D ratio especially for female offspring, which might be mediated by abnormal adipose accumulation in the fingertip. Therefore, the present findings suggest that high prenatal testosterone could be a risk factor both for Japanese men and women with ASDs, elucidating one potential etiology of ASDs in women.
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spelling pubmed-44606872015-06-10 Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders Masuya, Yasuhiro Okamoto, Yuko Inohara, Keisuke Matsumura, Yukiko Fujioka, Toru Wada, Yuji Kosaka, Hirotaka Mol Autism Research BACKGROUND: The prevalence of autism spectrum disorders (ASDs) is higher in men than in women. The extreme male brain theory proposes that excessive prenatal testosterone activity could be a risk factor for ASDs. However, it is unclear whether prenatal sex hormone activity is a risk factor for women. The ratio of the length of the second to fourth digits (2D:4D) is considered to be a biomarker of the prenatal ratio of testosterone to estrogen. Therefore, this study compared the 2D:4D ratios of women with and without ASDs to determine if prenatal sex hormone activity could be a risk factor for ASDs in women. METHODS: The study included 35 Japanese men with ASDs, 17 Japanese women with ASDs, 59 typically developed (TD) Japanese men, and 57 TD Japanese women. We measured digit lengths and compared the 2D:4D ratios among the four groups. We also examined the relationship between the 2D:4D ratio and the autism-spectrum quotient score of each group. RESULTS: In our cohort, men with ASDs tended to have lower right-hand 2D:4D ratios relative to TD men. In contrast, the right 2D:4D ratios in women with ASDs were higher compared to those of TD women. No significant correlations were found between the 2D:4D ratios and the autism-spectrum quotient scores in any group. The higher right 2D:4D ratios in women could not be explained by age or full-scale intelligent quotients. This group difference was not found for the left 2D:4D or right–left 2D:4D ratios. CONCLUSIONS: We found a reverse direction of abnormality in the right 2D:4D ratio for men and women with ASDs. It has been posited that high prenatal testosterone levels lead to a lower 2D:4D ratio. However, a recent animal study showed that testosterone injection to dam leads to a higher right 2D:4D ratio especially for female offspring, which might be mediated by abnormal adipose accumulation in the fingertip. Therefore, the present findings suggest that high prenatal testosterone could be a risk factor both for Japanese men and women with ASDs, elucidating one potential etiology of ASDs in women. BioMed Central 2015-06-09 /pmc/articles/PMC4460687/ /pubmed/26060570 http://dx.doi.org/10.1186/s13229-015-0028-x Text en © Masuya et al. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Masuya, Yasuhiro
Okamoto, Yuko
Inohara, Keisuke
Matsumura, Yukiko
Fujioka, Toru
Wada, Yuji
Kosaka, Hirotaka
Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title_full Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title_fullStr Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title_full_unstemmed Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title_short Sex-different abnormalities in the right second to fourth digit ratio in Japanese individuals with autism spectrum disorders
title_sort sex-different abnormalities in the right second to fourth digit ratio in japanese individuals with autism spectrum disorders
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4460687/
https://www.ncbi.nlm.nih.gov/pubmed/26060570
http://dx.doi.org/10.1186/s13229-015-0028-x
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