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Wednesday, January 30, 2013

Fetal Alcohol Syndrome or Not? The Shocking Results

Fetal alcohol spectrum disorder (FASD) is a broad term which refers to birth defects in the fetus caused by high maternal levels of alcohol consumption during pregnancy. A fetus is a developing human that is inside the mother from the end of the 8th week to birth. There are numerous FASD subtypes, the most common of which is fetal alcohol syndrome (FAS).

FAS, which was first described in 1968, is a pattern of mental and physical deficits that involves specific facial abnormalities (e.g., small eye openings, thin upper lip), growth failure, and is the leading cause of mental retardation in the Western world. For patients who do not meet full criteria for FAS (e.g., have slight facial abnormalities, normal growth) a diagnosis of partial FAS can be given. Some use the terms fetal alcohol effects, alcohol-related birth defects, and alcohol-related neurodevelopmental disorder but each have been sources of controversy.

Diagnosis of FASD relies on clinical coding system criteria but there are no objective biomarkers (e.g., blood test results, imaging findings) to confirm the diagnosis. As a result, the condition can be over-diagnosed.
Children presenting with signs of FASD are sometimes referred for genetic testing during the course of a diagnostic evaluation to determine is there may be another explanation for the patient’s presentation although this is not routinely done. In a recent article in the American Journal of Medical Genetics: Part A, researchers from The Netherlands evaluated 27 children referred to a genetics department between 2005 and 2010 who were suspected of having FASD. The results may surprise you.

First, when the researchers applied the most widely used coding systems for FASD based on clinical criteria (e.g., facial abnormalities, growth abnormalities), they found that more than half of the children did not meet criteria for FASD. Even more interesting is that 30% of the children appeared not to have confirmed prenatal alcohol exposure. Two of these children were found to have abnormal microstructural rearrangements of chromosomes (structures that contain genes). Genetic testing also found that in 92% of children had factors other than prenatal alcohol exposure that could have affected their intellectual functioning, such as social deprivation and intellectual disabilities inherited from family members.

The lesson from this study is that things are not always as they seem and that clinicians need to think critically when evaluated cases of suspected FASD. This includes referral for genetic testing.

Suggested reading: A Mother's Story of Raising a Child with Fetal Alcohol Syndrome
 
Reference: Abdelmalik N, van Haelst M, Mancini G, Schrander-Stumpel C, Marcus-Soekarman D, Hennekam R, Cobben JM. (2013). Diagnostic outcomes of 27 children referred by pediatricians to a genetics clinic in the Netherlands with suspicion of fetal alcohol spectrum disorders. Am J Med Genet A. 161(2):254-60.

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