New study reveals additional possible genetic origin of autism

The rate of autism in the world and in Israel is on a constant upward trend as researchers continue to try and analyze its causes. A new study, published in the journal Pediatrics, revealed an additional possible genetic origin of autism.

Researchers have found that when one of the siblings in the family is on the autistic spectrum, another sibling has a high chance of also being diagnosed on the autistic spectrum.

In the last decade, the prevalence of autism has risen to one in 36, and scientists around the world are trying to find the reasons for this. The current hypotheses are that the increase in the age of fathers increases the risk, in particular when the father's age approaches 50, as well as the possibility that the increase in awareness also increases the rate of diagnoses.

The diagnosis of autism includes a series of developmental disorders that affect the ability of the child or adult to respond and communicate with their environment. According to estimates, one out of every 200 children in Israel is diagnosed on the autistic spectrum, with 80% of them being boys.

The disorders are usually diagnosed around age two and are expressed in a series of deficits in social and emotional interaction. Those affected by the disorder avoid making eye contact, have difficulty understanding and responding to other emotions, have difficulty understanding insinuations or sarcastic comments, have a limited range of interests, prefer to be alone than to be in the company of others, feel comfortable dealing with objects, have attention deficit hyperactivity disorder and have difficulty adapting to changes. Children on the spectrum also tend to suffer from difficulties regulating touch and noise, and therefore, some of them are helped by wearing headphones.

Factors which contribute to higher chances of autism

Researchers found many factors that contributed to a higher chance of autism. For example, young siblings of autistic women had a 34.7% risk of being diagnosed with autism, compared to a 22.2% chance of developing autism in siblings of autistic men.

However, in general, the chance of autism was higher in boys: 25.3% of men were diagnosed with autism, compared to 13.1% of women. In terms of race, in white families, it was found that autism spectrum disorder in another sibling had a 17.8% prevalence, while in the other races, autism in two siblings in the family was at a rate of 25%. 

The mother's education was also found to have an effect. Among mothers with a lower education, the rate of autism in two siblings was 32.6%; among mothers who graduated from high school, the recurrence of autism in another child was 25.5%; in women with a bachelor's degree, 19.7% and a master's degree 16.9%.

The authors of the study concluded, based on the findings, that the rate of autism is seven times higher in families that already have one autistic child than in the general population, and concluded that the results emphasize the need for close developmental monitoring of babies and children in families where one autistic child is diagnosed.

"We have known for years that there is an over-incidence of autism in families where there is one diagnosed person," says Dr. Ravit Haleli, a specialist in child psychiatry from Shalvata Mental Health Center, Be’er Ya’acov.

"The more severe the disorder and the more significant the impairment, the earlier it is discovered in development. These include motor difficulties, difficulty establishing contact, and difficulties in sensory development, hyper or hyposensitivity. However, there are many cases of diagnosis at later ages and even after puberty," she added.

"The recommendation to parents is that if one or more of the typical signs of autistic disorder appear, a a specialist in psychiatry or child development should be contacted. The earlier one can identify and diagnose, the earlier tailored help can be provided the child and the family, giving a better possibility of influencing the rest of life in terms of abilities and achievements."