CLN6 disease
CLN6 disease is a progressive, inherited neurological disorder belonging to a group of conditions known as neuronal ceroid lipofuscinoses (NCLs) or Batten disease.
Overview
CLN6 disease primarily affects the nervous system. While symptoms typically appear in childhood, they can occasionally manifest in adulthood. The disease is characterized by the accumulation of proteins and other substances in lysosomes, which leads to the progressive death of nerve cells.
Symptoms
Childhood Onset
Children with CLN6 disease typically experience:
- Developmental regression (loss of previously acquired skills)
- Recurrent seizures (epilepsy)
- Difficulty coordinating movements (ataxia)
- Muscle twitches (myoclonus)
- Impaired speech (dysarthria)
- Vision loss
- Declining intellectual function
Adult Onset
Adults, typically diagnosed after age 30, may experience epilepsy, ataxia, dysarthria, and progressive loss of intellectual function. Vision loss is less common in adult-onset cases.
Causes
Mutations in the CLN6 gene cause this condition. The CLN6 protein is located in the endoplasmic reticulum and is thought to help cells dispose of materials they no longer need. Most childhood-onset mutations result in an abnormal protein that is quickly degraded, leading to a severe reduction in functional protein. Adult-onset mutations often result in a protein with reduced, rather than absent, function, which may explain the later onset of symptoms.
Inheritance
CLN6 disease is inherited in an autosomal recessive pattern. Both copies of the gene in each cell must have mutations for the disease to occur. Parents of an affected individual are carriers who typically do not show signs of the condition.