Endocrine Abstracts (2008) 17 P37

Increased incidence of low birthweight, prematurity and antenatal complications in Prader Willi syndrome

WF Paterson1, R McGowan1, A Smyth1, A Cooke2 & MDC Donaldson1


1Department of Child Health, Royal Hospital for Sick Children, Glasgow, Scotland, UK; 2Department of Medical Genetics, Royal Hospital for Sick Children, Glasgow, Scotland, UK.


The Prader Willi syndrome (PWS) is a complex, neurodevelopmental disorder resulting from absence of expression of imprinted genes in the 15q 11–13 region, usually due to deletion in the paternal chromosome (pd15q) or disomy of the maternal chromosome 15 (upd). Prompt diagnosis of PWS is beneficial for counselling families, managing the hypotonia and poor feeding that characterise the perinatal period and facilitating early interventions that may improve body composition and motor development. An increased incidence of prematurity and low birthweight (LBW) has been reported in PWS, together with obstetric symptoms such as reduced fetal movement, polyhydramnios and malpresentation.

Aims: a) To determine the incidence of prematurity (gestation <37 weeks), LBW (<2.5 kg) and typical antenatal features; and b) to investigate the relationship between prematurity vs age at clinical diagnosis and duration of nasogastric feeding (NGF) in subjects who have attended a multidisciplinary PWS clinic at RHSC, Glasgow since 1991.

Methods: Following Ethics approval and informed consent, data were collected from a Birth Questionnaire completed by the parent, the subject’s case records and maternal medical records (where available).

Results: Fifty-three (32 M) of a possible 61 subjects were recruited. Molecular genetic analysis was carried out in 50 subjects: pd15q (36); upd (10); 15q translocation (1); imprinting defect (1); nk – analysed elsewhere (1); no defect found (1). Median (range) BW (kg) and gestation (weeks) were 2.80 (1.69–3.99) and 40 (30–43) in males and 2.58 (1.94–3.93) and 38 (33–43) in females. Preterm delivery occurred in 14 subjects (26.4%) and LBW in 16 (30.8%; 11 preterm). Despite incomplete obstetric data, polyhydramnios was reported in 10 subjects, breech presentation in 9 and induction of labour in 11. Decreased fetal movements were recorded in 46/49 subjects (94%). Median (range) age at clinical diagnosis was 45.5 days (4 d–12.8 y) in 12 preterm vs 292 days (birth–46 y) in 37 term subjects. NGF was continued for 31 (2–234) days in 13 preterm vs 21.5 (3–365) days in 30 term subjects.

Conclusion: The incidence of prematurity and LBW in our PWS cohort markedly exceeds the national average. The diagnosis of PWS should be considered in small, preterm babies who are hypotonic with poor feeding, particularly if there is a history of decreased fetal movements and/or other obstetric complications.

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