Angelman's Syndrome (AS) is a rare neurogenetic syndrome.


Features present in all patients:

(1) severe developmental delay

(2) balance and/or movement disorder (gait ataxia, tremulous movement of limbs, unsteady or clumsy gait, jerky movements, excessive chewing or mouthing, wide-based gait, etc)

(3) behavioral problems (frequent laughing, frequent smiling, apparent happy demeanor, easy excitability, hypermotoric behavior, etc)

(4) speech impairment with decreased use of words; receptive and non-verbal communication better than verbal skills

Common features (present in over 80% of patients)

(1) delayed, disproportionate growth in head circumference, often with microcephaly

(2) seizures, usually starting in early childhood

(3) abnormal EEG (large amplitude slow-spike waves)


Features seen in 20-80% of patients:

(1) flat occiput

(2) occipital groove

(3) prognathia

(4) protruding and/or thrusting tongue

(5) sucking and/or swallowing disorder, feeding disorder during infancy

(6) truncal hypotonia

(7) wide mouth with wide-spaced teeth

(8) scoliosis

(9) increased sensitivity to heat

(10) constipation

(11) strabismus

(12) abnormal sleep-wake cycles and/or decreased need for sleep

(13) uplifted, flexed arm

(14) hypopigmented skin, light hair and light eye color compared to other family members

(15) fascination with water or crinkly items

(16) abnormal food-related behaviors and/or obesity

(17) hyperactive lower extremity deep tendon reflexes (DTR)


Developmental history:

(1) normal prenatal and birth history

(2) normal head circumference at birth with no major birth defects observed

(3) forward progression in development but often delayed

(4) no loss of skills with time

(5) structurally normal brain on imaging studies with or without mild cortical atrophy or dysmyelination


Laboratory findings:

(1) normal chemistry and metabolic profiles

(2) normal hematological profiles


To read more or access our algorithms and calculators, please log in or register.