Lesch-Nyhan syndrome history and symptoms
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aarti Narayan, M.B.B.S [2]
Overview
LNS is characterized by three major hallmarks: neurologic dysfunction, cognitive and behavioral disturbances, as well as uric acid overproduction (hyperuricemia). Damage to the basal ganglia causes victims to adopt a characteristic fencing stance due to the nature of the lesion. Some may also be afflicted with anemia (macrocytic). Virtually all patients are male, and male victims suffer delayed growth and puberty, and most develop shrunken testicles or testicular atrophy. Female carriers are at an increased risk for gouty arthritis, but are usually otherwise unaffected.
History
- The initial symptoms of Lesch-Nyhan syndrome begin in first few months of life itself. Classically, when the child is 3-5 months old, a delay in motor development is noticed along with hypotonia and failure to achieve milestones.
- Between 6-18 months of age, symptoms of spasticity and abnormal involuntary movements appear, which may be misdiagnosed as cerebral palsy. The motor and neurological symptoms progress until 3-6 years.
Symptoms
Overproduction of uric acid
- Orange colored crystals in diapers
- Nephrolithiasis
- Gouty arthritis
Nervous system impairment
- Developmental delay: evident by 3- 6 months of age.
- Decreased muscle tone (hypotonia)
- Difficulty crawling or walking
- Lack of speech is also a very common trait associated with LNS.
- Irritability
- Extrapyramidal involvement:
- Abnormal involuntary muscle contractions
- Loss of motor control,
- Writhing motions,
- Arching of the spine
- Pyramidal system involvement:
Self-injuring behavior
- Patients affected are cognitively impaired and have behavioral disturbances that emerge between two and three years of age.
- The uncontrollable self-injury associated with LNS also usually begins at three years of age.
- The self-injury begins with biting of the lips and tongue and as the disease progresses, affected individuals frequently develop finger biting and head banging.
- The self-injury can increase during times of stress. Self-mutilation is a distinguishing characteristic of the disease and is apparent in 85% of affected males.
- The majority of individuals are cognitively impaired, which is not easy to determine because of the behavioral disturbances and motor deficits associated with the syndrome.
- In many ways, the behaviors may be seen as a psychological extension of the compulsion to cause self-injury: rejecting desired treats or travel, repaying kindness with coldness or rage, failing to answer test questions correctly despite study and a desire to succeed, provoking anger from caregivers when affection is desired, and so on.
- Compulsive behaviors also occur, including aggressiveness, vomiting, spitting, and involuntary swearing, or coprolalia. The development of this type of behavior is sometimes seen within the first year, or in early childhood, but others may not develop it until later in life.
LNS in females
- While carrier females are generally asymptomatic, they do experience an increase in uric acid excretion, and some may develop symptoms of hyperuricemia, and suffer from gout in their later years.
- Testing in this context has no clinical consequence, but it may reveal the possibility of transmitting the trait to male children. Women may also require testing if a male child develops LNS. In this instance, a negative test means the son's disease is the result of a new mutation, and the risk in siblings is not increased.
- Females who carry one copy of the defective gene are carriers with a 50% chance of passing the disease on to their sons. In order for a female to be affected, she would need to have two copies of the mutated gene, one of which would be inherited from her father.
- Males affected with LNS do not usually have children due to the debilitating effects of the disease. It is possible for a female to inherit an X chromosome from her unaffected father, who carries a new mutation of the HGPRT gene.
- Under these circumstances, a girl could be born with LNS, and though there are a few reports of this happening, it is very rare. The overwhelming majority of patients with LNS are male.