Maternal prenatal male hormones associated with autism

 

This was originally noticed as a change in the ratio between the length of the 2nd and 4th fingers.  In prenatal androgen excess there is a change, with the 4th finger being relatively longer than in normal cases.

 

The research was done to see if other signs of raised male hormones might be found in autistic children.

 

See testosteronism below.

 

 

 

 

 

 

The 2D:4D ratio of significance in understanding prenatal hormones

 

 

Testosteronism:

this is the suggestion that the mothers of autistic children have more androgenic hormones in their blood while incubating the foetus or the hypothesis that autistic traits are increased following prenatal exposure to abnormally high levels of testosterone caused by congenital adrenal hyperplasia

 

Ingudomnukul E, Baron-Cohen S, Wheelwright S, Knickmeyer R. Elevated rates of testosterone-related disorders in women with autism spectrum conditions. Horm Behav. 2007 May;51(5):597-604. (they simply asked the mothers for signs of this: hirsuitism, tomboyism i.e. not specific. They found an excess of them in the mothers of the autistic children as compared to controls)

 

Knickmeyer RC, Baron-Cohen S. Fetal testosterone and sex differences in typical social development and in autism. J Child Neurol. 2006 Oct;21(10):825-45.  )They have followed this one up a lot but the proof is very difficult to come by). 

 

Baron-Cohen S, Knickmeyer RC, Belmonte MK. Sex differences in the brain: implications for explaining autism. Science. 2005 Nov 4;310(5749):819-23.  They have done quite a lot of work on the finger sizes (which vary according to pre-natal androgens) of autistic children.

 

Geier DA, Geier MR. A prospective assessment of androgen levels in patients with autistic spectrum disorders: biochemical underpinnings and suggested therapies. Neuro Endocrinol Lett. 2007 Oct;28(5):565-73 (Morning blood samples collected following an overnight fast, compared to the pertinent reference means, showed significantly increased relative mean levels for: serum testosterone (158%), serum free testosterone (214%), percent free testosterone (121%), DHEA (192%), and androstenedione (173%). By contrast, compared to the pertinent reference mean, the relative mean level of FSH (51%) was significantly decreased. Additionally, at least one of the androgen attributes examined exceeded its recognized laboratory age- and sex-specific reference range in 81.4% (57 of 70) of the patients examined.  – All this shows that the increased androgen compounds were associated with a fall in FSH as you would expect if the androgens were being over-produced rather than the FSH being over excreted by the pituitary.  Beware, there is a tendency in autism to over interpret high or low levels when often the levels are within normal ranges even if they are higher than usual.  These authors recommend routine clinical measurement of androgens as a result of their findings

 

Tordjman S, Anderson GM, McBride PA, Hertzig ME, Snow ME, Hall LM, Ferrari P, Cohen DJ. Plasma androgens in autism.  J Autism Dev Disord. 1995 Jun;25(3):295-304.  (they measured slightly different and they were the same in the ausitic patients and controls).

 

Howard JM. This could be due to maternal testosterone... Arch Dis Child. 2006 Jul;91(7):622; author reply 622.

 

Knickmeyer RC, Baron-Cohen S, Auyeung B, Ashwin E. How to Test the Extreme Male Brain Theory of Autism in Terms of Foetal Androgens? J Autism Dev Disord. 2008 Mar 8 

 

Baron-Cohen S, Knickmeyer RC, Belmonte MK. Sex differences in the brain: implications for explaining autism. Science. 2005 Nov 4;310(5749):819-23. Review.  They put over the brain and personality changes that are associated with excess male changes.

 

Falter CM, Plaisted KC, Davis G. Male Brains, Androgen, and the Cognitive Profile in Autism: Convergent Evidence from 2D:4D and Congenital Adrenal Hyperplasia. J Autism Dev Disord. 2008 Mar 7

 

Manning JT, Baron-Cohen S, Wheelwright S, Sanders G. The 2nd to 4th digit ratio and autism. Dev Med Child Neurol. 2001 Mar;43(3):160-4. Children with autism had lower than expected 2D:4D ratios and children with AS higher ratios than expected in relation to their fathers' 2D:4D ratio. It was concluded that 2D:4D ratio may be a possible marker for autism which could implicate prenatal testosterone in its aetiology.

 

 

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