Tag: Lesch- Nyhan Syndrome

Lesch- Nyhan Syndrome

LESCH-NYHAN SYNDROME

Q. 1

Lesch Nyhan syndrome is associated with deficiency of?

 A

HPRT(partial)

 B

HPRT(total)

 C

PRPP(partial)

 D

PRPP(total)

Q. 1

Lesch Nyhan syndrome is associated with deficiency of?

 A

HPRT(partial)

 B

HPRT(total)

 C

PRPP(partial)

 D

PRPP(total)

Ans. B

Explanation:

A complete deficiency of HPRT, the Lesch-Nyhan syndrome, is characterized by hyperuricemia, self-mutilative behavior, choreoathetosis, spasticity, and mental retardation. A partial deficiency of HPRT, the Kelley-Seegmiller syndrome, is associated with hyperuricemia but no central nervous system manifestations. In both disorders, the hyperuricemia results from urate overproduction and can cause uric acid crystalluria, nephrolithiasis, obstructive uropathy, and gouty arthritis. Early diagnosis and appropriate therapy with allopurinol can prevent or eliminate all the problems attributable to hyperuricemia but have no effect on the behavioral or neurologic abnormalities.

Ref: Burns C.M., Wortmann R.L. (2012). Chapter 359. Disorders of Purine and Pyrimidine Metabolism. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison’s Principles of Internal Medicine, 18e.

 


Q. 2

Lesch Nyhan syndrome is due to deficiency of:

 A

Hypoxanthine phosphoribosyl transferase

 B

Xanthine oxidase

 C

Purine phosphorylase

 D

Adenosine deaminase

Q. 2

Lesch Nyhan syndrome is due to deficiency of:

 A

Hypoxanthine phosphoribosyl transferase

 B

Xanthine oxidase

 C

Purine phosphorylase

 D

Adenosine deaminase

Ans. A

Explanation:

A i.e. Hypoxanthine phosphoribosyl transferase

Quiz In Between



Lesch- Nyhan Syndrome

LESCH- NYHAN SYNDROME


LESCH- NYHAN SYNDROME

Main Features

  • It is X-linked Recessive disorder.
  • It is caused due to complete deficiency of Hypoxanthine guanine phosphoribosyl transferase (HGPRT deficiency).
  • It affects only males.
  • Increased production of purine nucleotide from PRPP via De Novo pathway.
  • Purine degraded into uric acid and its level increases.

Clinical features

  • Hyperuricemia
  • Gouty arithritis
  • Urinary stones
  • Intellectual disability
  • Dystonic movement
  • Dysarthric speech
  • Self mutilation (irresistible urge to bite the fingers and lips)
  • Megaloblastic anaemia

Diagnosis

  • Hyperuricemia
  • HGPRTase enzyme acitivity in RBCs is deficient

Treatment

  • Allopurinol
  • Alkalanization of urine
  • High fluid intake

Exam Important

  • It is a sex linked disorder. (X Linked Recessive Disorder)
  • The structural gene of HGPRT is located on X-chromosome.
  • There is a complete deficiancy of HGPRT 
  • Self mutilation is one of the characteristic feature of the syndrome.
  • Allopurinol is used in the treatment.
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