Treatment Hurdle: Syndromic Obesity

Today’s post is another excerpt from “Best Weight: A Practical Guide to Office-Based Weight Management“, recently published by the Canadian Obesity Network.

This guide is meant for health professionals dealing with obese clients and is NOT a self-management tool or weight-loss program. However, I assume that even general readers may find some of this material of interest.


Syndromal forms of obesity pose an important challenge to treatment. A large number of syndromes are associated with childhood-onset obesity. These include obesity as a clinical feature and are often associated with mental retardation, dysmorphic features and organ-specific developmental abnormalities. While there is some evidence to support the use of meal replacements, very low-calorie diets, medications and even surgery in these patients, no long-term efficacy studies have been conducted to date.

Prader-Willi Syndrome

Prader-Willi syndrome is the most common syndromal cause of obesity, with an estimated prevalence of about 1 in 25,000. It is an autosomal dominant disorder characterized by diminished fetal activity, obesity, hypotonia, mental retardation, short stature, hypogonadotropic hypogonadism, and small hands and feet. Hyperphagia is a dominant feature in Prader-Willi syndrome.

Bardet-Biedl Syndrome

Bardet-Biedl syndrome is a rare autosomal recessive disease characterized by obesity, mental retardation, dysmorphic extremities (syndactyly, brachydactyly or polydactyly), retinal dystrophy or pigmented retinopathy, hypogonadism or hypogenitalism (limited to male patients) and structural abnormalities of the kidney or functional renal impairment.

Other Genetic Disorders

Albright’s hereditary osteodystrophy is an autosomal dominant disorder characterized by short stature, obesity, skeletal defects, and impaired olfaction.

More recently, several human single-gene disorders, such as leptin deficiency, pro-opiomelanocortin (POMC) deficiency and melanocortin-4 receptor (MC4R) deficiency, have been identified. These mutations all result in severe obesity in childhood without the development of the pleiotropic features characteristic of recognized childhood obesity syndromes. The most common of these gene disorders is MC4R deficiency, which has no pathognomonic features. The diagnosis should be considered in cases of early onset familial obesity, usually with clear dominant inheritance.

© Copyright 2010 by Dr. Arya M. Sharma and Dr. Yoni Freedhoff. All rights reserved.

The opinions in this book are those of the authors and do not represent those of the Canadian Obesity Network.

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