Syndrome characterized by a series of physical,
mental, and neurobehavioral birth defects resulting from chronic alcohol
consumption during pregnancy.
Fetal Alcohol Syndrome
Five-year-old boy with fetal alcohol syndrome shows short palpebral
fissures, ptosis, and a smooth, long philtrum with a thin upper lip.
Alcohol Antenatal Exposition; Alcoholic Embryopathy.
First described in France by J. Lemoine in 1968 and in the
United States by Jones and Smith in 1973. The literature is prominent
because FAS is considered the leading known cause of mental retardation
affecting all socioeconomic groups and races.
Between 0.5 and 5 per 1000 live births, making fetal FAS
the leading cause of mental retardation and birth defects. More frequent in
infants born to black mothers, especially those with ADH2-1/3 phenotype (an
unusual phenotype in white women). The incidence among children born to
heavy drinkers is 4%.
Not a genetic condition; rather it is a toxic
syndrome. However, women with the alcohol dehydrogenase 2 genotype 1/3
(ADH2-1/3) seem to be at greater risk for having an affected infant, but
this may be the result of greater ingestion of alcohol.
Unknown, but the teratogenic effect of alcohol on
the fetus is suspected to result from the formation of free radicals causing
cellular damage on the developing tissues of the fetus. Exposure early in
pregnancy is responsible for the defective organogenesis and abnormal
craniofacial development, whereas continuing alcohol exposure throughout
pregnancy causes growth deficiency. Neurodevelopmental effects caused by
alcohol are present during the three trimesters because the brain undergoes
development at all stages of pregnancy.
Diagnosis is clinical based on the physical findings in
the infant and the history of alcohol consumption during early pregnancy.
Diagnosis criteria have been established by the Institute of Medicine and
the National Academy of Sciences.
FAS is an ensemble of findings found in children
exposed to alcohol in utero. They include prenatal and postnatal growth
deficiency, short palpebral fissures, ptosis, flat midface, upturned nose,
smooth philtrum with thin upper lip, microcephaly, learning disabilities
associated with mild-to-moderate mental retardation, fine motor dysfunction,
hyperactivity, ventriculoseptal defect, atrial septal defect, and minor
Clinically suspected cardiac defects
should be ruled out with an echocardiogram.
Cooperation may be absent in some
children with behavioral dysfunction, so premedication is advisable. Rarely
patients have micrognathia and/or a short, webbed neck that may make direct
laryngoscopy and tracheal intubation more difficult.
In the presence of a cardiac defect,
antibioprophylaxis may be required.
Rovasio RA, Battiato NL: Ethanol induces morphological and dynamic
changes on in vivo and in vitro neural crest cells. Alcohol Clin Exp Res
Stoler JM, Ryan LM, Holmes LB: Alcohol dehydrogenase 2 genotypes, ...