Angelman syndrome

Angelman syndrome (AS, in English Angelman syndrome, or Happy Puppet Syndrome) is a disorder caused by a so‑called microdeletion of a chromosome. A microdeletion means the loss of a very small segment at a specific site on a chromosome. In this case, it concerns chromosome 15 and its long arm. It is a genetically determined disorder that occurs equally in boys and girls. It was first described in the literature in 1965 by the English physician Dr. Angelman. This disorder affects the nervous system.

Angelman syndrome is most commonly (in up to 70% of cases) caused by a deletion (loss) of segment 15q11‑q13 on the maternal chromosome 15. In 3%, the syndrome arises through so‑called paternal uniparental disomy (duplication of the genetic material of the paternal chromosome), in 6% Angelman syndrome is caused by a defect of genomic imprinting (a process in which the activity of a certain gene is regulated depending on which parent the gene was inherited from — only one gene is active). In less than 1% of cases, structural chromosome changes are found, and in 11% a mutation of the UBE3A gene is present. In some cases, the diagnosis is clinical (up to 10%), without detection of mutation, deletion, or other structural chromosome abnormalities. The changes that cause Angelman syndrome arise randomly de novo; only in a small percentage are these defects inherited. The frequency of Angelman syndrome in the population is approximately 1/16,000.

The causes of its origin are very closely correlated with the so‑called Prader–Willi syndrome. The two manifest differently outwardly, but the DNA segment that is missing on the chromosome is the same in both. Which syndrome a person will suffer from is determined by genomic imprinting (the degree of expression of a given gene depends on the parent of origin).

Symptoms:

Characteristic features of Angelman syndrome include delayed psychomotor development (which is noted as early as between 6–12 months), intellectual disability, impaired speech development, and disorders of coordination and balance. Many of these children suffer from epilepsy. Microcephaly (small head size) is typical.

These children are happy, smiling. They laugh a lot. When they are excited, they move their hands as if they were “flapping” them (hand‑flapping). Other signs include hyperactivity and short attention span. They are fascinated by water. Additional manifestations include sucking and swallowing difficulties, hypersensitivity to heat, and sleep disturbances (reduced need for sleep).

With age, patients with Angelman syndrome become less excitable, and sleep difficulties improve. Intellectual disability persists, speech development remains impaired, and seizure episodes continue. Abnormal EEG findings are present. In adulthood, characteristic facial features persist — the face becomes “rougher,” rounder, with light hair. Scoliosis of the spine is present.

Diagnosis:

The diagnosis can be established based on genetic testing that demonstrates the absence (deletion) on chromosome 15.

Treatment:

Treatment is only symptomatic, and people with this syndrome require lifelong assistance.

• málo rozvinutá reč - iba minimum slov, skôr neverbálny prejav
• ťažká mentálna retardácia
• motorické problémy - pripomínajúce pohyby bábiky
• bezdôvodné záchvaty smiechu
• porucha pozornosti
• hypotónia - znížené svalové napätie
• mikrocefália - "malá hlava"
• abnormálne EEG (vyšetrenie mozgu)
• škúlenie
• poruchy prehĺtacieho reflexu
• sploštené záhlavie hlavičky
• hyperaktivita
• epileptické záchvaty
• poruchy spánku
• nadšenie z vody
• skolióza chrbtice