Clinical diagnosis of the Prader-Willi Syndrome can be made using a score based on physical, mental and emotional findings. Genetic testing can be used to confirm the diagnosis.
Findings are divided into:
(1) major criteria
(2) minor criteria
(3) supportive findings that increase certainty in diagnosis but which are not scored
infantile central hypotonia
infantile feeding problems, failure to thrive
rapid weight gain between 1 and 6 years of age
characteristic facial features (narrow bifrontal diameter, almond-shaped palpebral fissures, narrow nasal bridge, downturned mouth with thin upper lip)
hypogonadism with genital hypoplasia and/or pubertal deficiency
developmental delay or mental retardation
• The original criteria from 1993 included cytogenetic abnormality with chromosome 15 (deletion 15q11-13). Modern techniques have made genetic testing diagnostic.
• The original criteria from 1993 included hyperphagia, food foraging and obsession with food.
decreased fetal movement and infantile lethargy
typical behavior problems (temper tantrums, stubbornness, manipulative behavior, obsessive-compulsive behavior, difficulty with change in routine, lying, stealing, aggressive)
sleep disturbance, sleep apnea
short stature for family by age 15 years
small hands and feet for height age
narrow hands with straight ulnar border
thick, viscous saliva
speech articulation defects
high pain threshold
temperature control problems
scoliosis and/or kyphosis
early adrenarche (normal adrenarche around 8 years of age)
unusual skill with jigsaw puzzles
normal neuromuscular studies
subscore for major criteria =
= SUM(points for major criteria)
subscore for minor criteria =
= SUM(points for minor criteria)
total points =
= (points for major criteria) + (points for minor criteria)
Major Criteria (Holm, 1993)
Major Criteria (Cassidy, 2001)
age <= 3 years of age
age > 3 years of age
• The fewer major criteria in Cassidy may reflect the reduction in number.
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