A 5-year-old girl who was developing normally until 18 months began to lose purposeful hand use, develop stereotyped hand-wringing movements, irregular breathing, and progressive intellectual regression. She has normal head circumference at birth but has developed acquired microcephaly. Seizures began at age 3. This presentation is pathognomonic of:

• A Angelman syndrome
• B Childhood disintegrative disorder
• C Landau-Kleffner syndrome
• D Rett syndrome ✓

Explanation

Rett syndrome is caused by mutations in MECP2 (methyl-CpG-binding protein 2) gene on Xq28; it affects almost exclusively females (lethal in hemizygous males). The classical stages: Stage I — normal development until 6–18 months; Stage II — developmental regression with loss of purposeful hand use, hand-wringing stereotypies, breathing irregularities, and acquired microcephaly; Stage III — plateau with seizures; Stage IV — late motor deterioration. Angelman syndrome features happy affect and absent speech from early on. Childhood disintegrative disorder has later, more global regression. Landau-Kleffner is an epileptic aphasia.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.