KIF1A Associated Neurological Disorder (KAND) is a neurodegenerative disorder caused by changes in the KIF1A gene. KAND causes a constellation of medical complexities. Symptoms first appear at birth or in early childhood.
What Is KAND?
SYMPTOMS OF KAND
While KAND is a degenerative disorder, progression of the disease may vary from person to person. People affected by mutations in KIF1A may experience different medical challenges. It is important to consult a physician immediately if you suspect your child could have KAND.
The following symptoms are commonly associated with KAND.
Hereditary Spastic Paraplegia
Hereditary Spastic Paraplegia (HSP) refers to a group of disorders that are characterized by progressive weakness and spasticity (stiffness) of the legs. HSP can be identified by gait abnormalities or limited range of motion in the legs. Complicated forms may be accompanied by other symptoms. These additional symptoms include impaired vision due to cataracts and problems with the optic nerve, ataxia (lack of balance and muscle coordination), epilepsy, cognitive impairment, peripheral neuropathy, and deafness.
Check out our Spasticity and KAND page for more information.
Optic Nerve Atrophy
Optic Nerve Atrophy (ONA) is caused by degeneration of the optic nerve, which carries vision information to the brain, this symptom results in poor vision. The person may have a reduced field of vision, be unable to distinguish details or colors, or have difficulty adjusting to light. In rare cases, blindness can occur.
Check out our Vision and KAND page for more information.
Ataxia
Ataxia is characterized by a lack of muscle coordination and balance, you may notice slurred speech, trouble eating and swallowing, rapid eye movements, deterioration of fine motor skills, difficulty walking (unsteady gait) and tremors.
Epilepsy
Characterized by unpredictable seizures, epilepsy in KAND can vary widely by seizure type and occurrence. People diagnosed with KAND should consult regularly with a neurologist. Some children affected by mutations in KIF1A experience Continuous Spikes and Waves During Sleep (CSWS). Seizure activity in KAND often occurs at night, and could go unnoticed during a routine EEG. Because this form of epilepsy is rare, overnight EEG monitoring helps diagnose and treat seizure types associated with KAND. Seizures that go unidentified and untreated can result in severe brain damage over time, and sometimes death. To learn more about seizures and KIF1A visit the Epilepsy Foundation website.
Check out our Epilepsy and KAND page for more information.
Hypotonia
Hypotonia is the medical term for low muscle tone. Infants and young children experiencing this symptom are often described as “floppy.” You may notice a child feeling limp when you hold them and showing less control of their neck muscles, causing the head to drop. It may also be difficult for them to place weight on their leg or shoulder muscles.
Intellectual Disability
Intellectual Disability (ID) most often results in developmental, speech and language delays in children. You may notice issues with verbal expression, difficulty expressing or receiving information, or problems with developing motor and fine-motor skills.
Cerebellar Atrophy
Cerebellar Atrophy is caused by degeneration of the cerebellum, the part of the brain that coordinates muscle activity. Cerebellar atrophy can result in impaired muscle coordination, a loss of balance, unsteady gait, slurred speech, difficulty swallowing or chewing, and blindness.
Peripheral Neuropathy
Peripheral Neuropathy is caused by damage to your peripheral nerves, which carry information from your brain and spinal cord to the rest of your body. This symptom can involve numbness in the hands and feet, a stabbing, burning or tingling pain throughout the body, extreme sensitivity to touch, and a lack of coordination.
Autism
Mutations in KIF1A can also result in a clinical diagnosis of Autism Spectrum Disorder (ASD). We are still learning about the genetic causes of autism; however, characteristics of ASD include difficulty with communication and interaction with other people; restricted interests and repetitive behaviors; symptoms that hurt the person’s ability to function properly in school, work, and other areas of life.
Attention Deficit Disorder
Attention Deficit Disorder is a disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.
DIAGNOSING KAND
KIF1A Associated Neurological Disorder can only be diagnosed through genetic testing. Because spasticity, epilepsy and hypotonia are common symptoms, medical professionals often mistake KAND for cerebral palsy or other more common diseases.
If you believe you have an incorrect diagnosis, you must seek genetic testing to receive a correct diagnosis and appropriate care. Because KAND is neurodegenerative, we don’t have time to wait. An incorrect diagnosis could impact the progressive nature of KAND.
Our leading research team at Chung Lab at Boston Children’s Hospital has evaluated over 100 families affected by KAND to understand the clinical features of this disease. If you have questions about KAND symptoms and how they affect you or a loved one, please contact the Chung Laboratory by emailing ASCENDstudy@childrens.harvard.edu.