Hyperphagic Short Stature Syndrome

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

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 intra-familial abuse.³ Familial studies suggest a genetic predisposition to the disease but a specific genetic defect has not been demonstrated.⁴
• It has an increased prevalence amongst children in foster care.⁵

Symptoms

Commonly reported during infancy are:

• Feeding problems
• Poor muscle tone
• Failure to thrive

Hyperphagia does not occur until approximately 3 years old and is associated with polydipsia. Symptoms of depression, sleep cycle disturbance and self injury (such as skin picking) also occur.

Signs

• The height for age is below the third centile, between 85% and 90% of expected height for age. Growth is often at a low normal rate parallel to the centile line. Head circumference is usually in proportion.
• Hyperphagic short stature is associated with learning disabilities.
• Affected children are frequently overactive and maintain a body mass index within the normal range despite over-eating.
• There is often history of wandering around the home at night in search of food. Food is often hoarded, usually in the child's room.

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.

• 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.

• 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.³
• If improvements are maintained, growth rates will also improve over a longer period of time.^1,2
• The psychosocial stress associated with and generated by hyperphagic short stature will require multidisciplinary support for the family and child.