🔅Huntington's disease (HD) is a rare, inherited condition that causes the progressive degeneration of nerve cells in the brain, affecting movement, cognition, and behavior.

– There is no cure for HD, but treatments can help manage some of the symptoms and improve the quality of life of people with HD and their families.

– Buckle up and get ready to learn and gain useful information about HD. Are you ready?

CAUSES OF HD

– HD is caused by: a mutation in the HTT gene, which is located on chromosome 4. The mutation consists of a repeated pattern of three nucleotides (CAG) in the DNA molecule that codes for the production of a protein called huntingtin.

– Normally, the HTT gene has less than 28 CAG repeats, but people with HD have 40 or more repeats. The extra CAG repeats alter the structure and function of the huntingtin protein; which leads to damage and death of nerve cells in certain areas of the brain.

– HD is inherited in an autosomal dominant pattern; which means that a person only needs to inherit one copy of the mutated gene from either parent to develop the disease. Each child of a parent with HD has a 50% chance of inheriting the mutation and developing the disease.

SIGNS AND SYMPTOMS OF HD

– Signs and symptoms are indications of the presence of a certain health/medical condition on an individual. The signs and symptoms of HD vary from person to person and usually develop gradually over time.

– They can be divided into three categories:

a). Movement disorders

b). Cognitive disorders

c). Psychiatric disorders

– Movement disorders include involuntary jerking or writhing movements (chorea), muscle stiffness or spasms (dystonia), slow or abnormal eye movements, impaired gait, posture, and balance, and difficulty with speech or swallowing.

– Cognitive disorders include problems with organizing, prioritizing, focusing, learning, remembering, processing thoughts, finding words, and making decisions.

– Psychiatric disorders include depression, anxiety, irritability, mood swings, apathy, social withdrawal, impulsivity, aggression, obsessive-compulsive behavior, psychosis, and suicidal thoughts or actions.

– The symptoms usually start between 30 to 50 years of age, but can begin earlier (juvenile HD) or later (late-onset HD). The disease progresses over 10 to 25 years and eventually leads to severe disability and death.

DIAGNOSIS OF HD

– The diagnosis of HD is based on a combination of medical history, physical examination, neurological and psychiatric assessment, brain imaging, and genetic testing.

🔅Medical history involves asking questions about the person's symptoms, family history of HD, and exposure to environmental factors that may affect the disease onset or progression.

🔅Physical examination involves checking the person's reflexes, muscle tone and strength, balance and coordination, hearing and vision, and sense of touch.

🔅Neurological and psychiatric assessment involves testing the person's memory, reasoning, mental agility, language skills, emotional state, behavior patterns, quality of judgment, coping skills, signs of disordered thinking, and evidence of substance abuse.

🔅Brain imaging involves using techniques such as computed tomography (CT) scan or magnetic resonance imaging (MRI) scan to show detailed images of the brain structure and function. These images may reveal changes in the brain areas affected by HD such as shrinkage (atrophy) or loss of tissue (volume). These changes may not be evident in the early stages of the disease. Brain imaging can also rule out other conditions that may cause similar symptoms.

🔅Genetic testing involves taking a blood sample and analyzing it for the presence of the CAG repeat mutation in the HTT gene. This test can confirm the diagnosis of HD with high accuracy. It can also be used for predictive testing in people who have a family history of HD but do not have symptoms yet. Predictive testing can tell if a person carries the mutation and will develop HD in the future but cannot tell when or how severe the symptoms will be. Predictive testing has benefits and risks that should be discussed with a genetic counselor before taking the test.

TREATMENT OF HD

– There is no cure or effective treatment for HD that can stop or reverse its progression. However, there are medications that can help manage some of the symptoms such as chorea, depression, psychosis, and mood disorders.

– Some examples are tetrabenazine, amantadine, fluoxetine, sertraline, quetiapine, risperidone, olanzapine, valproate, and carbamazepine.

These medications have side effects that should be monitored by a doctor.

– There are also therapies that can help improve communication, eating, swallowing, movement, and quality of life. Some examples are psychotherapy, speech therapy, physical therapy, occupational therapy, and palliative care. These therapies involve working with professionals such as psychologists, psychiatrists, neurologists, genetic counselors, social workers, nurses, dietitians, speech pathologists, physiotherapists, and occupational therapists.

– There are also clinical trials that are testing new drugs and interventions for HD that may offer hope for the future.

PREVENTION OF HD

– There is no way to prevent HD if a person has inherited the mutation from a parent. However, there are some strategies that may help delay the onset or slow down the progression of the disease. These include genetic testing and family planning, lifestyle modifications, and participation in research.

🔅Genetic testing and family planning which involves consulting a genetic counselor before having children to discuss the options and implications of passing on the mutation to the next generation. Some options are: prenatal testing, preimplantation genetic diagnosis, adoption, or using donor eggs or sperm.

🔅Lifestyle modifications involving adopting healthy habits such as eating a balanced diet, exercising regularly, avoiding smoking and alcohol, managing stress, and engaging in enjoyable and meaningful activities. These habits may help improve the general health and well-being of people with HD and their caregivers.

🔅Participation in research, that is, enrolling in clinical trials or observational studies that aim to find better ways to diagnose, treat, or prevent HD. This may help contribute to the advancement of scientific knowledge and medical care for HD.

SPECIALISTS INVOLVED IN TREATMENT AND ASSESSMENT OF HD

– HD is a complex and multidisciplinary condition that requires the involvement of various specialists and care centers. Some of the specialists who treat HD are: neurologists, psychiatrists, psychologists, genetic counselors, social workers, nurses, dietitians, speech pathologists, physiotherapists, occupational therapists, and palliative care specialists.

– These specialists work together to provide comprehensive and coordinated care for people with HD and their families. Some of the care centers that offer specialized services for HD are Huntington's disease centers of excellence, Huntington's disease clinics, Huntington's disease service providers, Huntington's disease support groups, and Huntington's disease research centers. These care centers provide access to expert diagnosis, treatment, counseling, education, support, and research opportunities for people with HD and their families.