X-linked recessive conditions

Question 1

Lesch-Nyhan

Answer 1

• defect on the long arm of the X chromosome
• 1/380,000-1/1000000
• deficiency of hypoxanthine-quanine phosphoribosyltransferase leads to build up of uric acid in the body fluids

Question 2

Lesch-Nyan features

Answer 2

• nearly all are male
• hypotonia
• delayed motor milestones
• spasticity and choreo-athetoid movements develop at 9 months
• sexiures in 50%
• uncontrollable self injury appears around 2-3
• kidney failure is usually the cause of death

Question 3

Hunter syndrome

Answer 3

• in males
• 2:130,000
• X-linked recessive
• deficiency in iduronate sulfatase
• glycosaminoglycans accumulate

Question 4

Symptoms of Hunters

Answer 4

• flared nostrils
• coarse face with flat nasal bridge
• hearing loss
• ataxia
• hernia
• hepatosplenomegaly
• joint stiffness
• recurrent infections of the ears and resp tract
• growth retardation
• CV abnormalities

Question 5

LD and Hunters

Answer 5

• not all have an LD
• those who do have a shortened life expectancy
• can have hyperactivity, delayed speech and loss of speech at 8
• restlessness
• inattention
• sleep abnormalities

Question 6

LIfe expectancy in Hunters

Answer 6

• 20-30 years

- death is due to neurodegeneration and complications of the disease