SNP Shot: Genomic Insights

Walker-Warburg syndrome (WWS) is a genetic condition passed down through families that impacts the development of muscles, the brain, and the eyes. It's the most serious form of congenital muscular dystrophy, a group of inherited disorders that cause muscle weakness and wasting (atrophy) from a very young age. Symptoms of WWS are noticeable at or shortly after birth, and due to the serious health problems it causes, most individuals with WWS don't live beyond childhood.

WWS impacts skeletal muscles, which are responsible for body movement. Infants with WWS have weak muscle tone (hypotonia), often described as being "floppy." This muscle weakness gradually gets worse.

The brain is also affected in WWS. A common brain abnormality is cobblestone lissencephaly, where the brain's surface lacks the usual folds and grooves, taking on a bumpy, irregular appearance resembling cobblestones. Additionally, individuals might develop fluid buildup in the brain (hydrocephalus) or have structural abnormalities in specific brain areas like the cerebellum and the brainstem. These brain changes result in substantial developmental delays and intellectual disability. Seizures can also occur in some cases.

Eye abnormalities are another defining feature of WWS. These can include abnormally small eyeballs (microphthalmia), enlarged eyeballs due to increased eye pressure (buphthalmos), clouded eye lenses (cataracts), and issues with the optic nerve, which transmits visual information to the brain. These eye problems lead to impaired vision.

Inheritance:

WWS follows an autosomal recessive inheritance pattern. This means that both copies of the responsible gene in each cell must contain a mutation for the disorder to develop. Individuals with one copy of the mutated gene are called carriers. The parents of a child with WWS each carry one copy of the altered gene but typically don't exhibit any symptoms of the condition themselves.