Angelman Syndrome (Happy Puppet Syndrome)

This 20-month-old girl was born to a 28-year-old mother (gravida 2, para 1) at 38 weeks' gestation. The pregnancy was uncomplicated, and vaginal delivery was normal.

The Apgar scores were 6 at 1 minute and 9 at 5 minutes. The neonate's birth weight was 2500 g (5 lb, 6 oz) and length, 47 cm (18.5 in).

The infant sat with support at 10 months of age, sat without support at 12 months, crawled at 13 months, and walked at 18 months. She had not yet begun to talk at 20 months. The child was noted to have frequent laughing episodes and often made flapping movements with her hands.

At 20 months, her weight was 9.6 kg (21 lb) (10th percentile) and height was 81 cm (2 ft, 8 in) (25th percentile); head circumference measured 45.5 cm (18 in) (3rd percentile). She had blue eyes, blond hair, flat occiput, large mouth, widely spaced teeth, protruding jaw, and hypoplasia of the mid face with sunken eyes. She walked with a stiff, unsteady, and jerky (“puppet”) gait.

Based on the clinical findings, Angelman syndrome, or happy puppet syndrome, was diagnosed. The diagnosis was confirmed by chromosomal studies using high-resolution techniques, which showed a maternally derived de novo deletion of chromosome 15q11-13.

Drs Edmond K. H. Liu and Alexander K. C. Leung of Calgary, Alberta, tell us that the classic features of Angelman syndrome include severe developmental delay; absence of speech; frequent and unprovoked laughing spells; ataxic, jerky movements; truncal hypotonia; hyperreflexia; microcephaly; brachycephaly; occipital groove; macrostomia; prognathism; midfacial hypoplasia; protrusion of the tongue when laughing; widely spaced teeth; strabismus; deep-set eyes; hand-flapping behavior; increased sensitivity to heat; and hypopigmentation of the skin, hair, and eyes compared with other family members.

Children with Angelman syndrome are prone to seizure disorders. Hyperactivity and sleep disturbances, which are common in childhood, tend to improve with age, whereas other anomalies usually persist.