Hyperphagic short stature syndrome

Psychosocial short stature is characterised by growth failure in association with emotional deprivation. Hyperphagic short stature is a variant of psychosocial short stature which has short stature in association with appetite and other behavioural problems. These children demonstrate biochemical evidence of growth hormone insufficiency, but they do not respond to growth hormone therapy. A change in social environment brings about catch-up growth and resolution of behavioural abnormalities.¹

Hyperphagia may be defined as an excessive and abnormal appetite for food. This is accompanied by an apparent lack of satiety and frequently eating to the point of vomiting or abdominal pain.

The syndrome was first described in the 1960s when it was grouped under the term psychosocial short stature.^{2 3}

Hyperphagic short stature syndrome epidemiology

The syndrome is rare and part of a small group of behavioural phenotypes associated with a physiological mechanism.¹

Risk factors

• Hyperphagic short stature is strongly associated with poor environmental and social conditions.

• The most common source of psychosocial stress for children with the syndrome is intrafamilial abuse.⁴ Familial studies suggest a genetic predisposition to the disease but a specific genetic defect has not been demonstrated.⁵

• It has an increased prevalence amongst children in foster care.⁶

Hyperphagic short stature syndrome symptoms (Presentation)¹

The diagnostic criteria are:

• Height below 3rd centile.

• Body mass index in normal range.

• Age greater than 2 years.

• At least one of:

  • Steals food at home and/or school.

  • Gorges and vomits.

• Two of the following, reflecting a persistent pattern of behaviour:

  • Eats excessively.

  • Polydipsia.

  • Hoards food.

  • Wakes at night and searches for food.

  • Forages for discarded food or rummages for food in bins.

Differential diagnosis⁵

Prader-Willi Syndrome

This is a congenital condition due to an anomaly at chromosome 15. It shares many of the characteristics of hyperphagic short stature. However, in contrast to hyperphagic short stature, Prader-Willi syndrome is associated with an obese body mass index, lethargy and more severe learning disabilities.

Investigations

• Standard behavioural measures can be used to detect hyperphagia and polydipsia - the major characteristic behavioural features of hyperphagic short stature.

• The syndrome is also associated with growth hormone insufficiency.

Hyperphagic short stature syndrome treatment and management¹

• Hyperphagia and sleep disruption resolve rapidly if the child's living conditions are improved.

• This is associated with a rapid increase in growth hormone to normal levels.⁴

• If improvements are maintained, growth rates will also improve over a longer period of time.^{2 3}

• The psychosocial stress associated with, and generated by, hyperphagic short stature will require multidisciplinary support for the family and child.