Sandhoff disease

What happens in this disease?

Two enzymes in the cells, hexosaminidase A and B, do not work well. Because of this, a fatty substance called GM2 cannot be broken down. The substance builds up in the nerve cells. Over time, the nerve cells in the brain and spinal cord are damaged.

Which symptoms can occur?

The most common form begins in infancy. Babies look normal until 3–6 months. There are also very rare, milder forms that begin in childhood or adulthood.

• Weakness in the muscles
• Loss of skills such as rolling over, sitting and crawling
• Being startled too much by loud sounds
• Seizures (fits)
• Loss of vision and hearing
• A cherry-red spot at the back of the eye (seen during an eye examination)
• Enlarged liver and spleen (sometimes)
• Problems with speech, balance and movement (in the later forms)

How is it diagnosed?

The doctor looks at the symptoms and the eye examination. The activity of the enzymes hexosaminidase A and B is measured in the blood. The diagnosis is confirmed with a genetic test.

Treatment and care

At present, there is no approved treatment specific to the disease. Care aims to ease the symptoms. Nutrition and fluid support, keeping the airway open and seizure treatment are important. New methods such as gene therapy are being researched. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through recessive inheritance. The mother and father are usually healthy carriers. For a couple who are both carriers, the chance of having an affected child is 1 in 4 in each pregnancy. Diseases of this kind may be more common in marriages between relatives. Genetic counselling is recommended.