Angelman syndrome
Causes of Angelman syndrome
In most cases of Angelman syndrome, the child's parents don't have the conditionand the genetic difference responsible for the syndrome occurs by chance around the timeof conception.
The typical characteristicsof Angelman syndrome are caused when the Angelman gene, known as UBE3A, is either absent or malfunctions. A gene is a single unit of genetic material (DNA) which acts as an instruction for the way an individual is made and develops.
A child usually inherits one copy of the UBE3A gene from each parent. Both copies are switchedon(active) in most of the body's tissues. However, in certain areas of the brain, only the gene inherited from the mother is active.
In most cases of Angelman syndrome (about 70%), the child's maternal copy of the UBE3A gene is missing (deleted), which means there's no active copy of theUBE3A gene in the child's brain.
In around 11% of cases, the maternal copy of the UBE3A gene is present butaltered (mutated).
In a small number of cases, Angelman syndrome occurs when a child inherits two copies of chromosome 15 from the father, rather than inheriting one from each parent. This is known as uniparental disomy.
It can also occurwhenthe copyof theUBE3A genethat comes from the mother behaves like it came from the father. This is known as an "imprinting defect".
In about 5-10% of cases, the causeof Angelman syndromeis unknown. Mostchildren inthese unexplained cases have different conditions involvingother genes or chromosomes.
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Read about Angelman syndrome, a genetic disorder that affects the nervous system and causes severe physical and intellectual disability
Characteristics of Angelman syndrome
The typical characteristics of Angelman syndrome aren't usually apparent at birth. A child withAngelman syndrome will begin to show signs of delayed development at around 6-12 months, such as being u
Causes of Angelman syndrome
In most cases of Angelman syndrome, the child's parents don't have the conditionand the genetic difference responsible for the syndrome occurs by chance around the timeof conception. The typical char
Diagnosing Angelman syndrome
Angelman syndrome may be suspected if a child's development is delayed and they have the syndrome's distinctive characteristics (see above). A blood sample can be takento confirm the diagnosis. Anumb
Managing Angelman syndrome
Some of the symptoms of Angelman syndrome can be difficult to manage, and you'relikely to need help from a wide range of different healthcare professionals. Your child may benefit from some of the fo
Help and support
The Angelman Syndrome Support Education and Research Trust (ASSERT) is a UK based charity providing information and support for parents and carers of people with the syndrome. As well as visiting th
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