Angelman syndrome (AS) was first described by Dr. Harry Angelman, who is an English physician. He noticed that there are 3 children under his care with similar developmental problems. They looked very happy and tend to flap their hands when excited. Therefore, Dr. Harry Angelman described these children in his paper called “Puppet Children” as these children’s characteristics just like the puppet.
Angelman Syndrome is now a familiar genetic disorder to most clinical geneticists and child neurologists in Cytogenetics. It is a recognizable syndrome which related to mental retardation and infantile seizures. Unlike Prader-Willi syndrome that I described last week, individual with Angelman syndrome is because the loss of maternally inherited region 15q11 – q13 of chromosome 15. Simple to say, the AS individual does not inherit the region 15q11 – q13 of chromosome 15 from his/her mother but only from father.
The Angelman syndrome clinical diagnosis is heavily dependent on the combination of some common behaviour like excessive laughter, apparent happiness with tremulous movements and gait ataxia (lack of coordination of muscle movement). Usually, the normal prenatal and birth history do not provides any clues in diagnosis of AS in Cytogenetics. CT scans, laboratory tests of blood and urine are usually normal including metabolic screening. Consequently, it is difficult for the clinical experts to encounter the AS especially when the child is less than 12 months of age. It is because the tremulous movements, ataxia and severe lack of speech may not be apparent during that time.
There are many common features of Angelman syndrome.
i. Severe speech deficit (usually absent speech)
ii. Mental retardation
iii. Microcephaly (small head)
iv. Seizures (convulsions in which AS patient’s body shakes rapidly and uncontrollably)
v. Developmental delay
vi. Feeding problems
vii. Hypopigmentation (the loss of skin color)
viii. Frequently drooling
ix. Tend to put objects in mouth
The facial features general physical appearances are generally normal for the individual of Angelman syndrome. As the child with AS growing up, the correct diagnosis may become evident when speech is essentially absent and the attempts at walking are compromised because of sever ataxia. In addition, the seizures will occur more frequently after 1 year of age.
In conclusion, the individual of Angelman syndrome may be hyperexcitable with excessive laughing, grabbing and pulling to engage others. They are just like the ‘Angels’ who always bring happiness to people. Usually, the parents may be the first to suggest the possibility of Angelman syndrome. Thus, earlier detection of this genetic disorder may help the children to overcome the learning problem through the assessment from the clinical experts.
My ultimate hope is this Cytogenetics and Cancer Research blog can really help in increasing the awareness of people about the genetic disorders and cancer.