Angelman Syndrome
Symptoms
Genomic Imprinting
EBE3A: role and effect of mutaion
Chromosome 15: UPD and deletions which give rise to Angelman Syndrome
Developmental delays, including no crawling or babbling at 6 to 12 months
Causes
Intellectual disability
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No speech or minimal speech
Difficulty walking, moving or balancing well
Frequent smiling and laughter
Happy, excitable personality
Sucking or feeding difficult
Trouble going to sleep and staying asleep
May also display
Seizures, usually beginning between 2 and 3 years of age
Stiff or jerky movements
Small head size, with flatness in the back of the head
Tongue thrusting
Hair, skin and eyes that are light in color
Unusual behaviors, such as hand flapping and arms uplifted while walking
Sleep problems
Curved spine (scoliosis)
Angelman Syndrome is caused by a mutation in the 15th chromosome called the ubiquitin protein ligase (UBE3A). .
This is the process of marking the parent of origin during the formation of sperm and egg cells.
Has major effects on prenatal development and placental biology.
Imprinted genes are emerging as key regulators of metabolic processes in both infants and adults. They can influence maintenance of body temperature, food intake and adiposity by acting on multiple tissues and pathways.
The UBE3A gene provides instructions for making a protein called ubiquitin protein ligase E3A.
Ubiquitin protein ligase E3A plays a critical role in the normal development and function of the nervous system
Both genes are generally inherited from ach parent however there are rare cases when both genes can be inherited from the paternal
Most cases of Angelman Syndrome occur when part of the maternal copy is missing or damaged
The mutation is generally caused by a missing segment in the maternal copy of the Chromosome 15.
It affects the nervous system which leads to the other symptoms of Angelman Syndrome
Uniparental Disomy is when a person receives 2 chromosomes or part of a chromosomes from a single parent but not the other
If both copies of Chromosome 15 are inherited from the paternal then Angelman Syndrome can occur. More commonly the maternal copy of Chromosome 15 is damaged which gives rise to Angelman Syndrome.