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.

SYMPTOMS OF KAND

While KAND is a degenerative disorder, progression of the disease may vary dramatically from person to person. People affected by mutations in KIF1A may experience different challenges, and the disorder does not affect any two individuals the same way. 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. 

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.

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.

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 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 proper diagnosis and care. Because of the neurodegenerative nature of KAND, incorrect diagnosis and treatment can be especially detrimental to the progressiveness of the disorder.

Our leading research team at Chung Lab at Columbia University Medical Center has interviewed 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 Chung Laboratory by emailing kif1a_study@cumc.columbia.edu.