Predictive factors of responsiveness to a body weight reduction program in Prader–Willi patients at 6 years of follow‑up

Prader–Willi syndrome (PWS), a multisystemic disorder caused by lack of expression of genes on the
paternally inherited chromosome 15q11.2-q13 region, is characterized by hyperphagia and childhoodonset
morbid obesity, A retrospective cohort study of 60 PWS patients, 38 females and 22 males,
undergoing a 6-year rehabilitation program was analysed. Mean age at the time of first admission was
27 ± 7 years, body weight (BW) was 97 kg ± 29 kg and height was 1.53 ± 0.09 m. Twenty-four patients
(40%) showed BW loss after 6 years of follow-up, seventeen (28%) remained stable and nineteen
(32%) gained BW. Responsiveness in term of BW reduction was less frequent in patients with the UPD
karyotype, karyotype del15 being more frequent among responsive patients. Furthermore, responsive
PWS subjects had a higher BMI (47 vs. 36 kg/m2), waist (123 vs. 106 cm) and hip (136 vs. 118 cm)
circumferences than non-responsive at the time of first hospitalization. Baseline body composition
and metabolic parameters did not differentiate between responsive and non-responsive patients.
Given the rarity of PWS and relative lack of studies, these results can be considered relevant because
based on a relatively large number of PWS patients followed up for a long term period.