Prader-Willi and Angelman syndromes. Analysis of the 15q11 region by MS-MLPA

Angelman syndrome is characterized by generally severe intellectual disability, severe speech impairment, gait ataxia and/or tremors of the extremities, and seemingly happy behavior. It is caused by an abnormal methylation pattern at 15q11.2-q13 or by mutations in the maternal allele of UBE3A.

Prader-Willi syndrome is a milder intellectual disability syndrome, accompanied by significant hypotonia, lack of appetite in early childhood, followed by excessive eating and gradual development of morbid obesity. Hypogonadism, short stature and a characteristic behavioral phenotype also stand out, with tantrums, stubbornness, manipulative behavior and obsessive-compulsive behaviors. It is caused by an abnormal methylation pattern at 15q11.2-q13.

Angelman: 1/10,000-20,000 newborns.

In Angelman syndrome, it is possible to find the cause in up to 90% of cases. 10% of all patients will present an alteration in UBE3A, however, a total of 80% of patients suffer from an alteration detectable by MS-MLPA. It can therefore be considered an ideal test as a first step when the suspicion of Angelman syndrome is very high.

The benefits derived from a genetic diagnosis in this context are especially aimed at closing the diagnosis and family genetic counseling.

Service indicated when the suspicion of Angelman syndrome, based on the patient’s phenotype, is very high.

If the patient suffers from Angelman syndrome, the cause is found using this technique in 80% of patients.