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Links of Comorbid Medical Conditions for Autism Spectrum Disorders between Parents and Their Affected Children
Many medical conditions have been reported to co-occur with autism spectrum disorder (ASD) in the same individual. However, it is not well known if these conditions also present in the parents of ASD children and if the parents’ conditions are directly associated with the medical conditions in their children. Given the prevailing broad autistic phenotypes in the parents of ASD children, we hypothesize that there is a shared etiology between ASD and some of its comorbid medical conditions, which links these conditions across generations in families with ASD-affected individuals.
Objectives:
To investigate if comorbid medical conditions in ASD-affected individuals could be attributed to the conditions in their fathers and/or mothers.
Methods:
From the Manitoba Population Research Data Repositoryin Canada, we identified all the ASD-affected individuals who were born between April 1979 and March 2010 and had the universal health care coverage for at least five years since birth. The ASD-affected individuals were matched with up to six controls using the propensity score method. An individual was regarded as an ASD case if he/she had at least two hospital and/or medical claims for ASD (based on the International Classification of Diseases, 9thedition code 299) after age two and at least one of the claims was made by a paediatrician or psychiatrist.
Information about the medical conditions, which affect the gastrointestinal, mental health, and neurological systems, was also collected from the Data Repository. Generalized linear mixed models were used to identify the ASD-associated medical conditions using the cases and their matched controls. Logistic regression was performed to estimate the contribution from the parents to the occurrence of the medical condition in the ASD-affected individuals.
Results:
After quality control, 1,933 ASD-affected individuals, 11,390 matched controls, and their parents were selected. Of the 100 medical conditions from the three disease categories, 30 had a prevalence ≥1% in either the ASD-affected individuals or their matched controls. Of these, 22 conditions were significantly associated with the increased ASD risk (p<0.0016 after Bonferroni correction for 30 multiple comparisons).
Five of the 22 medical conditions in the ASD cases could be attributed to one or both parents (all p<0.001): episodic mood disorders (ICD9 code 296 –mothers), anxiety, dissociative and somatoform disorders (ICD9 code 300 –mothers), depressive disorder, not elsewhere classified (ICD9 code 311 –mothers), and hyperkinetic syndrome of childhood (ICD9 code 314 –both parents), and functional digestive disorders, not elsewhere classified (ICD9 code 564 –both parents). The estimated effects (odds ratios) ranged from 1.93 to 3.45 for the mothers and from 1.59 to 5.42 for the fathers. Similar findings were obtained when our analyses focused on the parents’ medical conditions before the birth of their first child and when the parents of the cases were compared to the parents of the controls.
Conclusions:
Our preliminary results show that some of the comorbid medical conditions in ASD-affected individuals could be linked to their parents’ conditions, which suggests that genetic and/or environmental factors shared between parents and children may cause the occurrence of comorbid medical conditions in ASD-affected individuals.