Intellectual Developmental Disorder, X-Linked, Syndromic 33 (MRXS33)

What is Intellectual Developmental Disorder, X-Linked, Syndromic 33 (MRXS33)?

Intellectual Developmental Disorder, X-Linked, Syndromic 33 is a rare genetic syndrome and neurodevelopmental disorder characterized by intellectual disability and psychomotor delay. The syndrome, due to the way in which it is inherited, is most severe in males.

Because Mental Retardation is no longer used, former name Mental Retardation, X-Linked 33 is outdated.

What gene changes cause Intellectual Developmental Disorder, X-Linked, Syndromic 33 (MRXS33)?

Changes to the TAF1 gene are responsible for causing the syndrome. This is also linked to dystonia-parkinsonism syndrome. It is inherited in an X-linked recessive pattern.

Syndromes inherited in an X-linked recessive pattern generally only affect males. Males only have one X chromosome, and so one copy of a gene mutation on it causes the syndrome. Females, with two X chromosomes, only one of which will be mutated, are not likely to be affected.

What are the main symptoms of Intellectual Developmental Disorder, X-Linked, Syndromic 33 (MRXS33)?

The syndrome is characterized by intellectual disability and global developmental delay, impacting all areas of development. In some cases, individuals may also exhibit traits associated with autism

Growth delay, both before and after birth, is another main symptom.

Unique facial features of the syndrome include a small head, low set and protruding ears, a long face, a pointed chin, and sagging cheeks. Individuals also suffer from recurrent ear infections and in some cases hearing loss too.

How is it Diagnosed?

To find out if someone has a diagnosis of Intellectual Developmental Disorder, X-Linked Syndromic 33 (MRXS33), it is important to have a consultation and evaluation with a clinical genetic specialist.  Specialists may also suggest specific genetic testing or other types of tests to help reach a diagnosis.  FDNA’s AI technology can help speed up the diagnostic process by analyzing facial features and other health information.

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