Molecular characteristics

What causes intellectual disability syndromes related to the HERC1 gene?
HERC1 is a gene, i.e. a DNA template for building a protein, that codes for a protein that is believed to have important role in development and function of brain. Changes in HERC1 cause syndromic intellectual disability, most likely due to the decreased production as well as loss of function of the abnormal protein.

What is needed to confirm the diagnosis of intellectual disability syndromes related to the HERC1 gene?
This diagnosis is confirmed by performing genetic testing in an affected individual, which enables the detection of a disease-causing change in the HERC1 gene.

There are two possible ways to identify a HERC1 change:

  • Since the syndrome is not highly recognizable, most genetic changes in HERC1 will be found by whole exome sequencing.
  • If the individual’s characteristics raise the suspicion of an intellectual disability syndrome related to the HERC1 gene, direct sequencing of the HERC1 gene by Sanger sequencing can be performed.

The genetic testing can be arranged by a clinical geneticist and involves the collection of a sample of blood or saliva from the affected individual (and eventually the parents). Analysing the DNA of the patient and comparing it with the parents’ DNA may facilitate the detection of two HERC1 disease-causing changes in the child, one inherited from each parent.