Lesch Nyhan syndrome: symptoms and treatment

Lesch-Nyhan syndrome (LNS) is a rare and hereditary condition. Patients suffer from various physical and mental defects such as growth disorders, poor muscle control, very severe gout and mental retardation. Many patients with Lesch-Nyhan syndrome also engage in self-harm or self-mutilation. The treatment of LNS is often symptomatic, but progress is being made in the field of deep brain stimulation.

Lesch-Nyhan

  • What is Lesch-Nyhan Syndrome?
  • Self-mutilation
  • Neurological symptoms
  • Prognosis
  • Related conditions
  • Therapy

 

What is Lesch-Nyhan Syndrome?

Lesch -Nyhan syndrome (abbreviated as LNS ), also known as Nyhans syndrome, is a rare and hereditary condition caused by the lack of the enzyme hypoxanthine phosphoribosyltransferase (HPRT). This syndrome is caused by a defect in a gene and is inherited recessively via the X chromosome: the gene is carried by the mother, who does not have the disease herself, and is passed on to the son. Female carriers of the gene have an increased risk of gout in later life, but do not develop any further symptoms. However, in extremely rare cases, it is possible for a woman to inherit a mutated gene from her father and develop symptoms of Lesch-Nyhan Syndrome.
LNS is already present at birth. Patients have various mental and physical defects throughout their lives. The absence of HPRT causes a build-up of uric acid in all body fluids, and leads to problems such as very severe gout, poor muscle control and moderate mental retardation, which are already visible in the first years of life.

Self-mutilation

Another characteristic of Lesch Nyhan is self-mutilation, mainly visible when biting the lips and fingers, which usually starts in the second year of life. The abnormally high level of uric acid causes sodium crystals to form in the joints, kidneys, central nervous system and other parts of the body, resulting in serious kidney problems and swelling that are associated with very severe forms of gout. Patients often have stunted growth and very small or shriveled testicles (testicular atrophy).

Neurological symptoms

Neurological symptoms include facial grimaces, involuntary nodding and shaking of the head, and repetitive movements of arms and legs as seen in Huntington’s disease. Often straps must be used to limit movement so that patients do not injure themselves or others. The direct cause of these neurological abnormalities is still unknown. Due to the absence of the enzyme HPRT, the body hardly absorbs vitamin B12. Some patients develop a condition called megaloblastic anemia as a result of the vitamin B12 deficiency.

Prognosis

The prognosis for people with Lesch Nyhan Syndrome is not very favorable. Most will die between the ages of ten and thirty. However, with proper treatment by specialists it is possible to live longer. In developing countries where proper treatment and knowledge of the disease is lacking, patients often die before the age of ten.

Related conditions

A related disorder is Kelley-Seegmiller Syndrome . The cause of this can also be found in the enzyme HPRT, but only part of its effect is disabled. This disease also causes gout attacks and kidney stones, and often neurological abnormalities, but to a lesser extent.

Therapy

The treatment of LNS is symptomatic. Gout can be treated with allopurinol to control the level of uric acid. Kidney stones can be treated by lithotripsy or crushing, in which the stones are crushed by waves or laser. There is no clear treatment for the neurological symptoms. Sometimes medications such as carbidopa, levodopa, diazepam, haloperidol or phenobarbital are used to provide relief.
The spasms associated with the disease can be treated and reduced by the administration of baclofen or benzodiazepine.
Self-mutilation can be prevented or reduced by the use of sedative medication, but also by applying restraints and sometimes by training behavior. About 60% of patients have their teeth extracted at some point to prevent self-harm by biting. This is often seen as an effective method by family members. Because the risk of self-harm is higher when stressed, an attempt is made to keep this to a minimum.

Deep brain stimulation

discussing something called ” deep-brain stimulation ” as a possible treatment. This has been investigated in a number of patients with Lesch-Nyhan syndrome by Dr. Takaomi Taira in Tokyo and by Dr. Philippe Coubes in France. In some cases a decrease in spasms and self-mutilation was noted. This method was originally designed about 20 years ago for the treatment of people with Parkinson’s disease. In this treatment, wires are placed in a specific region of the brain in a patient who is not under anesthesia but with a local anesthetic while fully conscious. However, this is easier to perform in patients with Parkinson’s disease because they have no mental abnormalities and can therefore fully cooperate during the procedure.

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