Siderius X-Linked Mental Retardation syndrome

What is Siderius X-Linked Mental Retardation syndrome?

It is a rare genetic syndrome that affects only males. It presents mainly with intellectual disability.

X-linked mental retardation occurs in around 1 in every 5-6,000 males. However the Siderius type is much rarer and its exact prevalence is currently unknown. It is believed to affect less than a handful of individuals.

What gene changes cause Siderius X-Linked Mental Retardation syndrome?

It is caused by mutations in the PHF8 gene.

The syndrome is inherited in an X-linked recessive pattern. This makes it much more common in males. Females are the carriers of the mutated gene.

What are the main symptoms of Siderius X-Linked Mental Retardation syndrome?

The main symptoms of the syndrome include intellectual disability and developmental delay. This is usually identified as mild to moderate. This delay includes delayed motor development, and delayed speech development.

A cleft lip and palate are also common symptoms of the syndrome. Affected individuals also usually have unique facial features that include a long face, sloping forehead, broad nasal bridge, low set ears and large hands.

How does someone get tested for Siderius X-Linked Mental Retardation syndrome?

The initial testing for Siderius X-Linked Mental Retardation syndrome can begin with facial analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the need for further testing. A consultation with a genetic counselor and then a geneticist will follow.

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