A 6-year-old boy is brought to the office by his mother due to behavioral difficulties at school. His teacher has said, "He interrupts the class, doesn't listen, and cannot sit still for more than a few minutes." He has been sent home on a few occasions for hitting other children and taking their toys. The patient was adopted at age 6 months and his birth history is unknown. He runs around the office playing with various toys and is easily distracted. Vital signs are within normal limits. Weight and height are tracking on the 10th percentile, and head circumference is below the 5th percentile for age and sex. Physical examination reveals short palpebral fissures, a smooth philtrum, thin upper lip, and difficulty with both gross and fine motor coordination. Which of the following is the likely cause of this patient's condition?

Question

A 6-year-old boy is brought to the office by his mother due to behavioral difficulties at school.  His teacher has said, "He interrupts the class, doesn't listen, and cannot sit still for more than a few minutes."  He has been sent home on a few occasions for hitting other children and taking their toys.  The patient was adopted at age 6 months and his birth history is unknown.  He runs around the office playing with various toys and is easily distracted.  Vital signs are within normal limits.  Weight and height are tracking on the 10th percentile, and head circumference is below the 5th percentile for age and sex.  Physical examination reveals short palpebral fissures, a smooth philtrum, thin upper lip, and difficulty with both gross and fine motor coordination.  Which of the following is the likely cause of this patient's condition?

Quizplus · Accepted Answer

11ec160b_3b26_0007_9249_b945d50b9175_MD0001_00 This child's behavioral difficulties (distractibility, hyperactivity, hitting), growth retardation, poor coordination, and facial anomalies are suggestive of fetal alcohol syndrome (FAS). Alcohol is a teratogen that affects multiple organ systems (eg, heart, joints, kidneys, visual systems, auditory systems), most characteristically the CNS. Features of FAS include facial dysmorphism (short palpebral fissures, thin upper lip, smooth philtrum), growth retardation, and CNS involvement (structural and/or neurobehavioral). Intrauterine alcohol exposure can cause reduction in the volume of the caudate, striatum, thalamus, and cerebellum, resulting in abnormal reflexes, tone, and coordination. A decrease in the volume of the frontal lobe and dysfunction of the amygdala contribute to deficits in executive functioning, impulse control, and emotion regulation. Other neurobehavioral manifestations include cognitive impairment, learning disabilities, and social skill deficits. (Choice A) Fragile X syndrome is caused by unstable CGG (cytosine-guanine-guanine) trinucleotide repeats on the X chromosome. Features include intellectual disability; a long, narrow face; large, protruding ears; macrocephaly; and macroorchidism. (Choice C) Cocaine exposure in utero is associated with hypertonia and tremors in neonates and impairments in attention, language development, and behavioral regulation in school-aged children. It would not cause the facial anomalies seen in this patient. (Choice D) Rubella exposure in utero is associated with congenital heart defects, hearing impairment, and ocular abnormalities (eg, glaucoma, cataracts, retinopathy). (Choice E) Trisomy 18 (Edwards syndrome) is associated with a small mouth and prominent forehead; pointy ears; and flexed, overlapping fingers. Horseshoe kidney and congenital heart defects may be present. Survival beyond one year of age is uncommon and associated with severe intellectual disability. (Choice F) Facial features in trisomy 21 (Down syndrome) include epicanthal folds, upslanting palpebral fissures, brachycephaly (back of the head symmetrically flattened), flat nasal bridge, and protruding tongue. It is associated with varying degrees of intellectual disability. Educational objective: Typical features of fetal alcohol syndrome include facial dysmorphism (short palpebral fissures, thin upper lip, smooth philtrum), growth retardation, neurological abnormalities, and behavioral difficulties. __________ References: Fetal alcohol syndrome and fetal alcohol spectrum disorders. (http://www.ncbi.nlm.nih.gov/pubmed/29094891) A review of the physical features of the fetal alcohol spectrum disorders. (http://www.ncbi.nlm.nih.gov/pubmed/27729236)

A 6-Year-Old Boy Is Brought to the Office by His