Calcification of intervertebral disc occurs in:
Ans: a (Alkaptonuria) Ref: Nelson, 17th ed, p. 403; 18th ed, p. 534AlkaptonuriaAR disorderDeficiency of homogentisic acid oxidase.Clinical manifestations of ochronosis and arthritis.Only sign in paediatric age group is urine colour change to black on standing. This is caused by oxidation and polymerization of homogentisic acid in alkaline pH.Degenerative changes in lumbar spine are quite characteristic with narrowing of joint spaces and fusion of vertebral bodies.High incidence of mitral and aortic valvulitis, calcification of the heart valves, and myocardial infarction is also reported.InvestigationDiagnosis is by measurement of homogentisic acid in urine.Homogentisic acid is a strong reducing agent giving -i-ve reaction with Fehling and Benedict reagent.Gene for alkaptonuria is mapped on chromosome 3TreatmentNo effective treatment. Drug used is nitisinone
Alkaptonuria
Phenylketonuria
Gout
Rickets
Inborn Errors of Metabolism