Signs and Symptoms
CLN7 is a subtype of Batten diseaseBatten disease is the common name for a broad class of rare, inherited disorders or diseases of the nervous system also known as neuronal ceroid lipofuscinoses, or NCLs. In these diseases, a defect in a specific gene triggers a cascade of problems that interferes with a cell’s ability to recycle certain molecules. The disease has several forms that share some of the same features and symptoms but vary in severity and age when symptoms first begin to appear. Each form is caused by a variant in a different gene. Although “Batten disease” originally referred specifically to the juvenile-onset form of NCL, the term Batten disease is increasingly used to describe all forms of NCL. The disease ultimately leads to shortened lifespan. with late infantile onset, which means that the signs and symptoms of CLN7 begin to show during early childhood years. Children living with CLN7 will often experience the first signs and symptoms of the disease between the ages of 2 and 7 years old. After disease onset occurs, the symptoms will continue to progress.
Birth Through Age 7
Children with CLN7 typically experience normal development until about the age of 2 years. Initial common signs and symptoms may include:
- Vision deterioration
- Recurrent seizures, or epilepsy
- Twitching movements (myoclonusBrief, shock-like jerks or twitching of a muscle (myoclonus).)
- Difficulty sleeping
- Motor clumsiness
- Loss of motor skills that were previously acquired (developmental regressionWhen a child loses an acquired function, milestone or fails to progress beyond a prolonged plateau after a period of relatively normal development.)
We noticed Gabriela was having more frequent seizures. They were always quick, and it looked like she was just nodding her head.
- Sara, mother of daughter living with CLN7
Adolescent years
As the disease continues to progress through adolescent years, other symptoms may become apparent:
- Cognitive decline and memory loss
Aashi can still see light and shadow, but her vision is limited. It was the next thing she lost after her motor skills. She’s usually in high spirits and will hum or make noises when she hears songs or nursery rhymes that she knows.
- Rishi, father of daughter living with CLN7
Childhood Years
Signs and symptoms may appear more severe during this stage. The signs that are most commonly seen during this time may include:
- Progressive loss of vision
- Difficulty coordinating movements (ataxiaThe difficulty with or loss of muscle coordination and bodily movements.)
- Loss of gross motor function, including the ability to walk
- Development of a speech impairment with gradual loss of speech abilities
Birth Through Age 7
Children with CLN7 typically experience normal development until about the age of 2 years. Initial common signs and symptoms may include:
- Vision deterioration
- Recurrent seizures, or epilepsy
- Twitching movements (myoclonus)
- Difficulty sleeping
- Motor clumsiness
- Loss of motor skills that were previously acquired (developmental regression)
We noticed Gabriela was having more frequent seizures. They were always quick, and it looked like she was just nodding her head.
- Sara, mother of daughter living with CLN7
Childhood Years
Signs and symptoms may appear more severe during this stage. The signs that are most commonly seen during this time may include:
- Progressive loss of vision
- Difficulty coordinating movements (ataxia)
- Loss of gross motor function, including the ability to walk
- Development of a speech impairment with gradual loss of speech abilities
Adolescent years
As the disease continues to progress through adolescent years, other symptoms may become apparent:
- Cognitive decline and memory loss
Aashi can still see light and shadow, but her vision is limited. It was the next thing she lost after her motor skills. She’s usually in high spirits and will hum or make noises when she hears songs or nursery rhymes that she knows.
- Rishi, father of daughter living with CLN7
Signs & Symptoms Reported by Caregivers
While the signs, symptoms, and age of onset of CLN7 may vary and can progress differently in each individual, there are common signs and symptoms that are consistent across people living with CLN7. The examples below come from parents of children with CLN7.
- Progressive loss of vision (reluctance to step off curbs, squinting to look at pictures, reads a book too close to face, sees things that aren’t there, especially at night)
- Attention disturbances, cognitive delay, and memory loss (isn’t meeting milestones, slow to respond verbally)
- Seizures (appearing to nod off, looks like they are startled awake, twitches and tremors)
- Clumsiness and challenges with gross motor function or coordination of movement (lack of agility, reluctance to run, difficultly hopping on one foot, tripping, falling)
- Deterioration of fine motor skills (challenges with scissors, needing a fat crayon instead of a pencil, difficultly picking up small objects)
- Speech impairment (uses simple words to express themselves, need support for missing words or letters)
Sources:
- Neuronal ceroid lipofuscinosis 7 (n.d.). Retrieved August 16, 2019, from link.
- Batten Disease Fact Sheet. (2019, June 24). Retrieved July 31, 2019, from link.
- Types of Batten Disease. (n.d.). Retrieved August 14, 2019, from link.
- CLN7 disease. (2019, July 16). Retrieved July 31, 2019, from link.
- Kousi, M., Siintola, E., Dvorakova, L., Vlaskova, H., Turnbull, J., Topcu, M., Yuksel, D., Gokben, S., Minassian, B.A., Elleder, M., Mole, S.E., Lehesjoki, A.E. (2009). MutationsA mutation is any inherited genetic change. The term “mutation” is being replaced by the term “variant.” in CLN7/MFSD8 are a common cause of variantA variant is a change in DNA. A variant may or may not cause disease. The following modifiers describe the variant: (i) pathogenic, (ii) likely pathogenic, (iii) uncertain significance, (iv) likely benign, or (v) benign depending on whether or not the variant causes disease. For example, a “pathogenic variant” may cause disease. The term “variant” has replaced the term “mutation.” late-infantile neuronal ceroid lipofuscinosis. Brain, 132(3): 810–819. Retrieved December 17, 2019, from link.
- Field resource conducted by Neurogene and Ten Bridge Communications, August 2019.
