Which combination of facial features is characteristic of fetal alcohol syndrome?

Which combination of facial features is characteristic of fetal alcohol syndrome?

• A. Macrocephaly and wide set eyes
• B. Normal facial features
• C. Microcephaly, short palpebral fissures, flat midface, smooth philtrum, thin upper lip
• D. Prominent jaw and chin

Answer: (C)

The key idea is the distinctive facial phenotype produced by alcohol exposure during early pregnancy, which disrupts facial development. Fetal alcohol syndrome typically shows a combination of microcephaly (small head size), short palpebral fissures (small eye openings), a flat midface, a smooth philtrum, and a thin upper lip. These features stem from alcohol’s interference with neural crest cell migration and facial tissue formation during weeks 3–8 of gestation, leading to midface hypoplasia and the smooth, thin-lipped upper lip pattern. This set of facial characteristics is what clinicians look for as characteristic signs, often along with growth deficiency and potential CNS impairment. Other descriptions, such as normal features or opposite traits like macrocephaly or a prominent jaw, don’t fit the typical FAS pattern.

The key idea is the distinctive facial phenotype produced by alcohol exposure during early pregnancy, which disrupts facial development. Fetal alcohol syndrome typically shows a combination of microcephaly (small head size), short palpebral fissures (small eye openings), a flat midface, a smooth philtrum, and a thin upper lip. These features stem from alcohol’s interference with neural crest cell migration and facial tissue formation during weeks 3–8 of gestation, leading to midface hypoplasia and the smooth, thin-lipped upper lip pattern. This set of facial characteristics is what clinicians look for as characteristic signs, often along with growth deficiency and potential CNS impairment. Other descriptions, such as normal features or opposite traits like macrocephaly or a prominent jaw, don’t fit the typical FAS pattern.