Hypocholesterolemia In Children and Adolescents with Autism: A Clinical Sample From Turkey

Background:  

Autism is defined as abnormalities in reciprocal social interaction and communication, and by the presence of restrictive or stereotyped interests and behaviors. A number of factors are being investigated including genetic, infectious, metabolic and environmental, with specific causes known in less than 10% to 12% of cases. Recent findings suggest the role of abnormal lipid metabolism in autism (Tierney et al, 2006; Aneja and Tierney, 2008; Kim et al, 2010).

Objectives:  

The aim of this study was to investigate the incidence of cholesterol deficiency in a group of subjects with autistic dis­order (AD).

Methods:  

Study group included 88 children and adolescents (74 male / 14 female) with a mean age of 8.3 ± 3.5 (2.8 – 16.6) years who met DSM-IV diagnostic criteria for AD (APA, 1994) by clinical assessment. All patients were recruited from Bakýrköy State Hospital for Mental Health and Neurological Disorders, Child Psychiatry Outpatient Clinic during May 2008 - April 2009. Children with any diagnosed genetic, metabolic, or neurological disorders were excluded from the study. Children with dietary restrictions and on psychopharmacotherapy also were excluded.

Results:  

The mean cholesterol level was 150.5 ± 28.7 (81.0 – 230.0) mg / dl. Sixteen subjects (18.2 %) had a cholesterol level lower than 100 mg/dl, which is below the 5th centile. The mean age of 16 participants with cholesterol levels below 100 mg/dl (10.1 ± 0.8 years) were higher than the other 72 subjects (7.9 ± 3.4 years). Five of 14 girls (35.7 %) and 11 of 74 boys (14.9 %) had low cholesterol levels. Pearson correlation analysis revealed that there was a relation between low cholesterol levels and age (p=.024) and a relation close to significance between low cholesterol levels and gender (p=.065).

Conclusions:  

Tierney et al (2006) reported that 19 % of children with autistic spectrum disorders had total cholesterol levels lower than 100 mg/dl. Our findings confirmed the high prevalence of abnormally low cholesterol levels in AD and support clinical significance regarding the possible role of cholesterol deficit in the etiology. Cholesterol is essential for brain development and myelination. Also cholesterol functions as a modulator of 5-HT1A and oxytocin receptors, and is a precursor for steroid hormones. It is likely that in some forms of ASD, the symptoms may be due to interaction of components that are sterol dependent.

Low serum cholesterol values are associated with increased violent behavior, suicide, depression, anxiety, and bipolar disease. As subjects with autism have high rate of comorbid psychiatric conditions, further studies are needed to investigate the relation between cholesterol levels and psychiatric problems.

References

1. Tierney E, Bukelis I, Thompson RE, Ahmed K, Aneja A, Kratz L, Kelley RI. Abnormalities of cholesterol metabolism in autism spectrum disorders. Am J Med Genet B Neuropsychiatr Genet 2006; 141B (6): 666-8.
2. Aneja A, Tierney E. Autism: the role of cholesterol in treatment. Int Rev Psychiatry 2008; 20(2): 165-70.
3. Kim EK, Neggers YH, Shin CS, Kim E, Kim EM. Alterations in lipid profile of autistic boys: a case control study. Nutr Res 2010; 30(4): 255-260.