Those with autism spectrum disorder, or ASD, display social impairments, language difficulties and repetitive or obsessive behaviors. It is a spectrum disorder as its severity and symptoms vary between individuals. The cause of autism is unknown, and researchers are investigating both genetic and environmental causes, says the National Institute of Neurological Disorders and Stroke, or NINDS. In 2006, researchers began investigating what role cholesterol plays in the symptoms of autism.
Cholesterol
Most people think of cholesterol as a dangerous artery-clogging substance, effective at increasing your risk of a heart attack. While it is true that many people with normal cholesterol production may need to think about decreasing their cholesterol consumption at some point in their lives, low cholesterol production in individuals with certain genetic disorders can cause many problems. Cholesterol is required for normal development of embryos and fetuses. It plays many roles in the proper development and function of the brain and spinal cord. Cholesterol also helps form your myelin, a fatty covering around your nerves that allows you to move in an instant.
Smith-Lemli-Opitz Syndrome, SLOS
SLOS is a genetic disorder where your body cannot make cholesterol, according to the "American Journal of Medical Genetics, Neuropsychiatric Genetics." Children with SLOS often have a variety of slight to severe facial abnormalities and mental retardation. Many children with SLOS, 53 percent according to one 1994 study, fit the criteria for autism. This study also reports that some of the children's behavioral abnormalities, including those consistent with autism, improve following administration of cholesterol supplements. These findings led researchers to investigate cholesterol levels in children with autism
Cholesterol & Autism
Researchers in the "American Journal of Medical Genetics, Neuropsychiatric Genetics" aimed to assess cholesterol levels in children with autism. None of the children from the study had cholesterol levels as low as children with SLOS, but 19 percent of children with autism have levels below the fifth percentile. This means that 19 percent of autistic kids have cholesterol levels lower than 95 percent of their peers. Researchers of this study concluded that children with autism may have some kind of cholesterol disorder other than SLOS.
Significance
Researchers believe that by learning more about SLOS, a disorder involving a single gene abnormality, and how its low cholesterol levels lead to autistic-like symptoms in some patients, they will be able to learn more about the genetics and role of cholesterol in autism spectrum disorders. Experts in the "International Psychiatric Review" suggest that non-SLOS cholesterol abnormalities involving many genes may cause the brain abnormalities and symptoms of autism.
Treatment
Whether treating children who have autism with cholesterol improves their symptoms is currently unknown. A clinical trial began in July 2009 for children ages 4 to 12 with autism spectrum disorder. The purpose of the trial is to measure cholesterol levels in children with autism, investigate whether those with low levels have more severe symptoms than those with normal levels, and determine whether administration of cholesterol improves autistic symptoms.
References
- National Institute of Neurological Disorders and Stroke: Autism Fact Sheet
- "International Review of Psychiatry: Autism: The role of cholesterol in treatment
- "American Medical Journal of Genetics, Neuropsychiatric Genetics": Abnormalities of Cholesterol Metabolism in Autism Spectrum Disorders
- Clinical Trials Feeds: Cholesterol in ASD, Characterization and Treatment
