Cohen Syndrome Health Article

Definition

Cohen syndrome is a very rare genetic disorder characterized by infantile hypotonia (a weakening of the skeletal muscles), childhood obesity and several malformations.

Description

Cohen syndrome was first described in 1973 by Dr. M. M. Cohen, Jr. in three children with distinct physical and developmental observations. Since then, over 100 cases have been reported throughout the world, offering the picture of an extremely rare disease with a wide range of clinical characteristics. The initial description given by Cohen included obesity, mental retardation, low muscle tone, narrow hands and feet, and distinctive facial features with prominent upper central teeth. The underlying cause of the disease remains unknown.

Cohen syndrome has also been referred to as Pepper syndrome, hypotonia-obesity-prominent incisors syndrome, obesity-hypotonia syndrome, and Mirhosseini-Holmes-Walton syndrome.

Genetic profile

Research has suggested that the gene for Cohen syndrome lies between 8q21.3 and 8q22.1. This refers to a location on the long arm of chromosome 8 between positions 21.3 and 22.1 and is a rough estimate of where the gene may lie. This region was originally referred to as CHS1 but has since become known as COH1. The phrase "COH1 gene region" is often used due to the fact that the exact location of the gene remains to be discovered.

Chromosomes are the genetic material passed down from generation to generation that tell a person's body how to work and how to grow. Each chromosome is composed of smaller pieces known as genes. A person inherits one set of 23 chromosomes from both the egg and the sperm of the parents. These chromosomes can then be matched into pairs, giving two copies of each chromosome and likewise two copies of each gene.

Cohen syndrome is an autosomal recessive disorder. Recessive means that both copies of the COH1 gene region must have a change or mutation for a person to be affected. An individual with only one changed COH1 gene region is not affected by the disease but can pass the disease on to a future child. These individuals are called carriers. If two carriers have a child there is a 25% chance with each pregnancy that the child will be affected. At this time prenatal diagnosis is not available.