Neuronal ceroid lipofuscinosis 3

Neuronal ceroid lipofuscinosis 3 (CLN3-NCL) is caused by changes (mutations) in the CLN3 gene. This gene provides instructions for making a protein whose function is unknown. However, it appears to be important for the normal function of cell structures call lysosomes.^[1]

Although researchers do not completely understand how mutations in the CLN3 gene lead to the signs and symptoms of CLN3-NCL, they appear to disrupt the function of lysosomes (structures in the cell that normally digest and recycle different substances). When the lysosomes don't work properly, lipopigments (materials made of fats and proteins) build up in cells of the brain and the eye as well as in skin, muscle, and many other tissues. Researchers believe that this build up plays a key role in the development of the many features of CLN3-NCL.^[1]

Carbamazepine and phenytoin may increase seizure activity and myoclonus (involuntary muscle jerks) in people with neuronal ceroid lipofuscinosis 3 (CLN3-NCL) and other types of neuronal ceroid lipofuscinoses (NCLs). In some cases, these medications have been associated with worsening of symptoms.^[2]

In one study of people with CLN3-NCL, valproic acid and clonazepam were noted to have severe side effects. More specifically, 50 percent of people receiving valproic acid had sleep disturbances or excessive sedation. Clonazepam seemed to stimulate salivation and respiratory secretions, increasing the risk of pneumonia.^[2]