Why Females are Less Likely to Have Autism than Males

Autistic Twins
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Male children are over 4 times more likely to be diagnosed on the spectrum than females, a prospect which has baffled the general community for years. Why is it that one gender is better able to fend off a disorder? Does it mean that the mutation does not exist, but that it is so subtle, it is nearly impossible to detect? A study of late has proven the biological makeup of a person does indeed provide the means to protect one against the effects of certain mutations.

Autism is a peculiar disorder that affects one's ability to function in the world. It is a genetic disorder that is accentuated by environmental factors. ADHD is one of the most common comorbid disorders, alongside phobias, OCD, and social anxiety disorder. It can be coupled with other disorders such as pica, which involves eating certain non-nutritional non-foods.

Gender and Genetics in 2011
One particular study looking into the gender differences concerning functionality and abilities of autistic individuals, found that:

  • Boys are diagnosed with autism 10 times more often than girls
  • Boys are over 4 times more likely to be on the spectrum
  • A gene called retinoic acid-related orphan receptor-alpha, or RORA, is implicated in autism
  • It was found that estradiol enhanced the expression of RORA where DHT suppressed it, protecting females against RORA deficiency
  • Researchers suspect that the second X-chromosome in females may shield them from the disorder

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Gender differences in Autistic Individuals
Previous articles have outlined certain theories that research has discovered to be true about gender differences when it comes to those on the spectrum:

  • Females show brain overgrowth from a younger age
  • Females show less gross motor and interpersonal deficits
  • Females perform better on processing speed, coding and symbol search
  • Males have deficits in motor coordination, inhibition and planning on top of basic motor speed
  • Males show greater levels of dyspraxia
  • Males perform better on block design

Why it was RainMAN and not RainWOMAN
A new study published last Thursday in the American Journal of Human Genetics, reprinted in the journal Cell, presented its conclusion that females need to have a lot more genetic anomalies in order to be diagnosed. The Economist added to the research facts by mentioning that attention deficit hyperactivity disorder (ADHD) is diagnosed around three times more often in boys than in girls, with “Intellectual disability” 30-50% more common in boys, as is epilepsy.

Here, specialists from US and Swiss universities looked at DNA samples from 15,585 individuals with autism and other neurodevelopmental disorders. “This is the first study that convincingly demonstrates a difference at the molecular level between boys and girls referred to the clinic for a developmental disability,” said Sébastien Jacquemont of the University Hospital of Lausanne in Switzerland, the study’s lead author. “The study suggests that there is a different level of robustness in brain development, and females seem to have a clear advantage.”

The exact results? Girls had mutations of the sort associated with abnormal neural development more often than boys. This, coupled with the extra X-chromosome which copies all the mutations and doubles it, means that females produce certain protections against showing these mutations outwardly. It may sound backward, but the human body is rather interesting in that sense. As such, because females are better at covering their disorders, only the more extreme cases show up in diagnoses.

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