2011 Group Project 7

Angelman Syndrome

Introduction

Angelman syndrome (AS) is a rare neurogenetic disorder, first described by Harry Angelman in 1956.

It is caused by maternal allele disruptions of a single gene-UBE3A. Either mutations or deletions of UBE3A are liable for a variety of symptoms.

Delayed development, seizures, motion malfunction, impairment of speech and a happy demeanor are the most frequent ones.

The syndrome is sometimes incorrectly referred to as "happy puppet" syndrome, due to frequent laughter and excitement.

About 1 in 25,000 newborn babies are affected by this disorder. There appears to be no discrepancy in males and females affected by it, and persons with the syndrome have a normal life span.

Up to now there is no cure for the syndrome, and current research does rather focus at improving life quality of patients with Angelman syndrome, than finding a cure.

Symptoms

Angelman syndrome causes a variety of symptoms, and the presented symptoms may vary at different ages.

In 1995 Williams et al embraced the observed clinical features of AS in a consensus statement, in order to present an appliance for clinicians.

These diagnostic criteria were updated in 2005.

Angelman Syndrome individuals show the most distinct disease pattern from 2 to 16 years of age. In most cases at least 8 of the symptom traits are showen.

4 characteristics appear in 100% of the cases:

Delayed development: becoming apperant by the age of 6 to 12 months.

Motion and or balance malfunction

Behavior patterns like unmotivated laughter, frequent excitement; often including body movements, Hypermotoric behavior

Impairment of speech

3 characteristics appear in more than 80% of the cases:

Abnormalities in head circumference, microcephaly

Seizures

EEG shows specific pattern

Furthermore, there is a range of major and minor traits in patients with Angelman Syndrome:

Physical appearance

Behavioural appearance

Differences between patients with deletions and mutations