Lesch–Nyhan

Syndrome (LNS)

De Jesus, Joan Mae V.

Cobey, Marjorie P.DMD 2D

LESCH–NYHAN SYNDROME (LNS)

•Also known as Nyhan's syndrome, Kelley-Seegmiller syndrome and Juvenile gout

•It is a hereditary disorder of purine metabolism, characterized by menntal retardation, self-mutilation of the fingers and lips by biting, impaired renal function, and abnormal physical development.

• It is a recessive disease that is linked to the X chromosome

• It is caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT)

SIGNS AND SYMPTOMS

Overproduction of uric acid

• Urate crystal formations, which look like orange sand, are deposited in diapers of the babies

• Kidney stones• Blood in the urine• Dysphagia (difficulty

swallowing)• Swelling of the joints• Vomiting

Behavioral Abnormalities

• Impaired cognitive functon

• Self-mutation• Aggression/Impulsion

Neuroglial disabilitiesGrimacing experience

Spasticity

Chloreathetosis (involuntary repetitive movement)

Decreased muscle tone

Athetosis (uncontrolled spastic muscle movements of the arms and legs)

Involuntary writhing movements

Chorea (purposeless repetitive movements)

Moderate mental retardation

Irritability

Pathogenesis Overproduction of Uric

Acid

- associated with hyperuricernia

- can produce Nephrolithiasis (kidney stones) with renal failure and solid subcutaneous deposits (tophi)

Behavioral Elements

- cognative disfunction and aggressive and impulsive behaviors

-severe self injurious behavior is common

Neurological disability- includes dystonia (abnormal firmness of tissue or muscle), choreoathetosis (abnormal movement of body), and occasional ballismus (jerky movement of arms or legs)- other signs include spasticity and hyperreflexia

This condition is inherited in an X-linked recessive pattern

Lesch–Nyhan Syndrome (LNS)

Formation of uric acid crystals in the joints leads to inflammation

Gout causes sudden, yet severe attacks of pain, redness, and tenderness and inflammation of the joints

PODAGRA

Behavioral Abnormalities

self-mutilation of the lips by biting

Behavioral Abnormalities

self-mutilation of the fingers by biting

Overproduction and accumulation of uric acid

Exams and Tests

There may be a family history of this condition. The doctor will perform a physical exam. The

exam may show: Overexaggerated reflexes Spacity Blood and urine tests may reveal high uric acid

levels. A skin biopsy may show decreased levels of the HGP enzyme.

Prenatal diagnosis is possible by DNA testing of fetal tissue drawn by amniocentesis or chorionic villus sampling (CVS)

Treatment

-LNS itself cannot be treated-Only the symptoms of LNS can be treated.-The drug allopurinol may be used to control excessive amounts of uric acid. -Kidney stones can be treated with lithotripsy -To help reduce some of the problem behaviors and neurological effects of LNS :

Diazepam (Diastat, Valium) Haloperidol (Haldol)

Phenobarbital (Luminal)

Prognosis:

-The prognosis for LNS is poor because there are no treatments for the neurological effects of the syndrome.

-Persons with this syndrome usually require assistance walking and sitting and generally need a wheelchair to get around.

-The build-up of excessive uric acid in the body causes painful episodes of self-mutilation and may result in severe retardation and death.