Neuronal ceroid lipofuscinoses (Batten disease): Year of the Zebra

Neuronal ceroid lipofuscinoses, or NCLs, also sometimes referred to as Batten disease, are a group of rare inherited neurodegenerative disorders that mainly affect children and adolescents and are one of the main causes of childhood dementia.

They belong to a larger group of diseases known as lysosomal storage disorders, a group of metabolic conditions that result in the inability of a cell to break down certain substances, causing them to build up, ultimately leading to cell damage and death. With NCLs, there is a buildup of ceroid lipofuscin and other toxic waste products within neurons due to defects in lysosomal proteases or related enzymes.

There are 14 different known subtypes of NCLs, named CLN1 to CLN14 each resulting from a specific gene mutation. Most of these mutations are inherited in an autosomal recessive pattern, meaning that an individual needs to inherit two copies of the mutated gene, one from each parent, to develop the disorder.

Alright, now NCLs predominantly affect the retina of the eye and brain. The most common symptoms include progressive visual impairment that eventually leads to blindness; and seizures, respectively.

With early infantile onset, there is usually muscle weakness, as well as a delay in development of motor milestones, like lifting the head or crawling. Later on, children may experience poor coordination, unsteady walking, and progressive loss of acquired motor abilities.

Infantile and juvenile onset are also characterized by learning difficulties and developmental regression, meaning that a child may lose certain developmental skills that they had previously acquired.