Warburg Micro syndrome (WARBM)

What is Warburg Micro syndrome?

It is a rare neurodevelopment syndrome that affects mainly the eyes and brain development. Issues with vision and intellectual disability are the main symptoms of the syndrome as a result. There are currently less than 100 cases recorded of the syndrome worldwide, making it extremely rare.

This syndrome is also known as:
Micro Syndrome; WARBM; Micro syndrome

What gene changes cause Warburg Micro syndrome?

The genes responsible for causing the syndrome have been identified as RAB18, RAB3GAP1, RAB3GAP2, and TBC1D20. However, the syndrome has also been diagnosed in individuals without mutations in any of these genes which suggests other genes might also be responsible for causing it.

The syndrome is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means an affected individual receives one copy of a mutated gene from each of their parents, giving them two copies of a mutated gene. Parents, who carry only one copy of the gene mutation will not generally show any symptoms but have a 25% chance of passing the copies of the gene mutations onto each of their children.

What are the main symptoms of Warburg Micro syndrome?

The main symptoms include vision and eye abnormalities including small eyes and small corneas. In some affected infants, cataracts (a clouding of the cornea) is often present at birth. Optic atrophy, degeneration of the optic nerve between the eyes and the brain, can also be associated with the syndrome. This in turn affects an individual’s vision.

In some individuals with the syndrome atronic pupils are present. These are pupils that are very large, shaped irregularly and react poorly to the light.

Severe intellectual disability is also common to the syndrome. This includes developmental delays and in severe cases an inability to sit, walk or talk. Autistic features are also associated with the syndrome in some individuals.

Anomalies in brain development associated with the syndrome include an underdevelopment of the bridge that connects the right and left parts of the brain, a shrinkage of the brain and a shrinkage of the part of the brain responsible for coordination and balance, as well as anomalies involving too many folds in the brain and folds that are exceptionally small.

Unique facial features associated with the syndrome include a narrow mouth, wide bridge of the nose and deep set eyes.

Progressive muscle weakness is also a symptom of the syndrome and this leads to individuals not being able to move their arms and legs. While infants with the syndrome often present with reduced muscle tone and floppiness, over time this muscle tone goes to another extreme and increases to the point where it causes spasticity or stiffness in the legs. This in turn cases the permanent fixture of joints in a bent or straightened position. In time this also spreads to the arms.

Underdeveloped genitals are common with the syndrome. In males this includes a small penis, underdeveloped scrotum and undescended testes. In females this may affect the development of the clitoris and labia minora.

How is Warburg Micro syndrome diagnosed?

To find out if someone has a diagnosis of Warburg Micro syndrome, 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.