What are the characteristic abnormalities of Fetal Alcohol Syndrome (FAS), including the three primary features?

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From the Guidelines

Fetal Alcohol Syndrome (FAS) is a condition characterized by three primary abnormalities: distinctive facial features, growth deficiencies, and central nervous system problems, as documented in the most recent guidelines 1. The diagnosis of FAS requires documentation of these three findings, including all three dysmorphic facial features (i.e., smooth philtrum, thin vermillion border, and small palpebral fissures), prenatal or postnatal growth deficit in height or weight, and CNS abnormality, as stated in the guidelines 1.

Key Abnormalities:

  • Distinctive facial features, including a smooth philtrum, thin upper lip, and small eye openings
  • Growth deficiencies, manifesting as lower than average height and weight both before and after birth
  • Central nervous system abnormalities, including structural brain abnormalities, microcephaly, and neurological problems that lead to intellectual disabilities, learning difficulties, poor coordination, hyperactivity, and problems with attention, memory, and judgment These abnormalities occur because alcohol crosses the placenta and interferes with fetal development, particularly affecting brain development, as noted in the guidelines 1. The severity of FAS varies depending on factors such as the amount and timing of alcohol exposure during pregnancy, and there is no cure for FAS, making prevention through complete abstinence from alcohol during pregnancy the only effective approach, as emphasized in the most recent guidelines 1.

From the Research

Fetal Alcohol Syndrome

Fetal alcohol syndrome (FAS) is a condition that results from prenatal alcohol exposure, leading to a range of physical, cognitive, and behavioral abnormalities.

  • Mental retardation and microcephaly are commonly observed in individuals with FAS 2.
  • FAS can also result in neurobehavioral sequelae, which may present at birth or appear later in development 2.

Abnormalities Present in Fetal Alcohol Syndrome

The three main abnormalities present in Fetal Alcohol Syndrome are:

  • Growth Deficits: Growth deficits, including short stature and low weight, are common in individuals with FAS.
  • Facial Abnormalities: Facial abnormalities, such as small eye openings, thin upper lip, and smooth philtrum, are characteristic of FAS.
  • Central Nervous System Abnormalities: Central nervous system abnormalities, including mental retardation, microcephaly, and attention deficits, are also present in individuals with FAS 2, 3, 4, 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The effects of prenatal alcohol on the central nervous system.

Recent developments in alcoholism : an official publication of the American Medical Society on Alcoholism, the Research Society on Alcoholism, and the National Council on Alcoholism, 1991

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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