Which are the causes of Snyder-Robinson Syndrome?

Snyder-Robinson Syndrome (SRS) is a rare genetic disorder that primarily affects males. It is characterized by intellectual disability, skeletal abnormalities, and other distinctive features. The syndrome is caused by mutations in the Spermine Synthase (SMS) gene, which is located on the X chromosome.

The SMS gene provides instructions for producing an enzyme called spermine synthase. This enzyme is involved in the production of spermine, a polyamine that plays a crucial role in various cellular processes, including cell growth, differentiation, and apoptosis (programmed cell death).

Mutations in the SMS gene disrupt the normal functioning of spermine synthase, leading to a deficiency of spermine. This deficiency affects multiple systems in the body, resulting in the characteristic features of Snyder-Robinson Syndrome.

Intellectual disability is a prominent feature of SRS. The exact mechanisms by which spermine deficiency leads to cognitive impairment are not fully understood. However, it is believed that spermine plays a crucial role in the development and function of the nervous system. Its deficiency may disrupt neuronal signaling and impair the formation and maintenance of synapses, leading to intellectual disability.

Skeletal abnormalities are another hallmark of Snyder-Robinson Syndrome. Individuals with SRS often have distinctive facial features, including a prominent forehead, a broad nasal bridge, and a wide mouth. They may also have abnormalities of the bones, such as scoliosis (curvature of the spine), kyphosis (excessive outward curvature of the upper back), or joint contractures (limited range of motion in the joints).

Other features that can be associated with SRS include hypotonia (low muscle tone), delayed speech development, seizures, and problems with coordination and balance. Some individuals may also experience gastrointestinal issues, such as constipation or gastroesophageal reflux.

Snyder-Robinson Syndrome is inherited in an X-linked recessive manner. This means that the condition primarily affects males, as they have only one X chromosome. Females can be carriers of the mutated gene but are typically unaffected due to the presence of a normal copy of the gene on their other X chromosome.

In conclusion, Snyder-Robinson Syndrome is a rare genetic disorder caused by mutations in the SMS gene, leading to a deficiency of spermine. This deficiency affects various systems in the body, resulting in intellectual disability, skeletal abnormalities, and other distinctive features. Further research is needed to fully understand the underlying mechanisms and develop potential treatments for this complex syndrome.