A male has a defect in the X chromosome of the 23rd pair. As children, people with this syndrome experience symptom that can range from mild to severe or even profound intellectual disability. This is known as .

The correct answer is: Fragile X Syndrome.

Explanation:

Fragile X Syndrome is a genetic condition that has an X-linked dominant inheritance, which means that this disorder is carried in a gene in the X chromosome (23rd pair) and will affect any child with one allele.

Given that males only get one X chromosome, while females get two, this condition tends to affect males on a deeper level.

People with Fragile X Syndrome suffer from intellectual disability (the average IQ in males is under 55), characteristic physical features such as a long and narrow face, big protruding ears, flexible fingers and large testicles. Autism and hyperactivity are also common.