Appendix

Consensus diagnostic criteriaOur questionnaire
Major criteria
Neonatal and infantile central hypotonia with poor suck, gradually improving with ageSevere floppiness at birth with later improvement
Poor suck at birth with later improvement
Feeding problems in infancy with need for special feeding techniques and poor weight gain/failure to thriveDifficulty feeding at birth (need for special feeding techniques)
Excessive or rapid weight gain on weight for length chart (excessive defined as crossing two centile channels) after 12 months but before 6 years of age; central obesity in the absence of interventionObesity during childhood, age when noticed, maximum weight ever and age when reached
Characteristic facial features with dolichocephaly in infancy, narrow face or bifrontal diameter, almond shaped eyes, small appearing mouth with thin upper lip, downturned corners of the mouth (3 or more required)
Hypogonadism with any of the following, depending on age:Males: undescended testes, surgery on testes, decreased facial and body hair, lack of voice change/age at voice change, early pubertal signs, small penis
(A) Genital hypoplasia, male: scrotal hypoplasia, cryptorchidism, small penis and/or testes for age (<5th centile); female: absence or severe hypoplasia of labia minora and/or clitoris
Females: does/did she have periods (no if only when on pill), age of first period, how many periods per year, early pubertal signs
(B) Delayed or incomlete gonadal maturation with delayed pubertal signs in the absence of intervention after 16 years of age (male: small gonads, decreased facial and body, hair lack of voice change; female: amenorrhoea/oligomenorrhoea after age 16)
Global developmental delay in a child younger than 6 years of age; mild to moderate mental retardation or learning problems in older childrenLearning difficulties
Hyperphagia/food foraging/obsession with foodTendency to overeat/obsession with food.
Deletion 15q11-13 on high resolution (>650 bands) or other cytogenetic/molecular abnormality of the PWS chromosome region, including maternal disomyGenetic testing done, result of testing, where testing was done
Minor criteria
Decreased fetal movement or infantile lethergy or weak cry in infancy, improving with ageDecreased movement of baby during pregnancy
Weak cry or inactivity as a baby
Characteristic behaviour problems: temper tantrums violent outbursts and obsessive-compulsive behaviour, tendency to be argumentative, oppositional, rigid, manipulative, possessive, and stubborn; perseverating, stealing, and lying (5 or more of these symptoms required)Frequency and severity of any: temper tantrums, skin picking, repetitive questioning, obsessional behaviour, violent/aggressive behaviour, fluctuations in mood, argumentative, lying, stealing, stubborn, any other behaviour problems
Sleep disturbance or sleep apnoeaDisturbed or noisy sleep
Short stature for genetic background by age 15 (in the absence of growth hormone intervention)Short height: heights of proband, mother, father, height centile. Growth hormone ever (dates)
Hypopigmentation: fair skin and hair compared to familyFair skin and hair compared with family
Small hands (<25th centile) and/or feet (<10th centile) for height ageSmall hands or feet (parents & researchers agree)
Narrow hands with straight ulnar border
Eye abnormalities (esotropia, myopia)Eye problems (short sight, long sight, squint)
Thick viscous saliva with crusting at corners of the mouthThick saliva with crusting at corners of mouth
Speech articulation defectsDifficulty with articulating words
Skin picking
Supportive findings
High pain thresholdHigh pain threshold (examples)
Decreased vomitingEver vomited: circumstances, frequency (0, <normal, normal)
Temperature instability in infancy or altered temperature sensitivity in older children and adultsNot feeling hot or cold when others are: abnormal temperature response
Scoliosis and/or kyphosisScoliosis or spinal curvature
Early adrenarche
Osteoporosis, thin bones, eg, easily broken
Unusual skill with jigsaw puzzlesUnusual skill with jigsaw puzzles
Normal neuromuscular studies