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CASE REPORT
  
Year : 2001  |  Volume : 67  |  Issue : 5  |  Page : 271-272

Alkaptonuria

Alka Dogra, GS Bajwa, Navjot Bajwa, Shallu Khurana 
 Department of Dermatology, Dayanand Medical College and Hospital, Ludhiana (Punjab), India

Correspondence Address:
Alka Dogra
Department of Dermatology, Dayanand Medical College and Hospital, Ludhiana (Punjab)
India

Abstract

A case of alkaptonuria, a rare autosomal recessive metabolic disorder is being reported. The patient presented with passage of dark coloured urine, cutaneous and scleral pigmentation and joint pains. The diagnosis was confirmed by the detection of homogentisic acid in the urine.



How to cite this article:
Dogra A, Bajwa G S, Bajwa N, Khurana S. Alkaptonuria.Indian J Dermatol Venereol Leprol 2001;67:271-272


How to cite this URL:
Dogra A, Bajwa G S, Bajwa N, Khurana S. Alkaptonuria. Indian J Dermatol Venereol Leprol [serial online] 2001 [cited 2020 Feb 29 ];67:271-272
Available from: http://www.ijdvl.com/text.asp?2001/67/5/271/11273


Full Text

 Introduction



Alkaptonuria is a rare metabolic disorder first described by Garrod.[1] The worldwide incidence in the population is 1:250000.[2] The disease is notably frequent in Czechoslovakia in which the incidence approaches 1:25000.[3] There are very few cases reported from India. It is characterised by deposition of oxidised homogentisic acid in fibrous and cartilaginous tissues, which manifests clinically as of dark urine (homogentisic aciduria), distinctive cutaneous pigmentation (ochronosis) and arthritis. [Figure:1] Arthropathy may cause disabilities but the life expectancy is usually normal.

 Case Report



A 50- year- old female, resident of Himachal Pradesh presented with the complaint of backache,pain in the hip,knee and shoulder joints, and inability to walk without support. There was history of the urine turing dark on standing since childhood There were no systemic complaints.There was no history of any drug intake. Family history was not contributory. On examination, black spots were seen bilaterally over the sclerae between the limbus and lateral canthus. Dark discoloration was seen on the index fingers and pinnae bilaterally. Oral mucosa was normal. The patient had a stooping posture and a short stepping gait. Examination of the spine revealed tenderness in the lumbar region and the movements were restricted in all directions. All the movements were decreased in the hip joints and shoulder joint. Bilateral rupture of the tendo­achilles was present. Chest expansion was within normal limits. Urine examination showed the presence of homogentisic acid. Radiological examination of the spine revealed marked osteoporosis, narrowing of disc space and calcification of the disc. Calcification was also seen around the knee joints.

 Discussion



Alkaptonuria inherited as an autosomal recessive condition is characterised by the deficiency of homogentisic acid oxidase in the kidneys and liver. Recently, alkaptonuria gene was assigned to human chromosome 3q 21-q 23.[4] This leads to accumulation of homogentisic acid, an intermediate metabolite of phenylalanine and tyrosine catabolism.[5] Ochronosis occurs because of the deposition of a melanin-like brownish black pigment, derived from the oxidised product of homogentisic acid in the connective tissues and cartilage. The only manifestation may become apparent as early as the third decade and may be the presenting complaint.[6] Cutaneous manifestations in the form of ochronosis appear in the fourth decade.The earliest signs may include pigmentation and thickening of the ear cartilage. The extensor tendons on the knuckles show a distinctive pigmentation. Mucosae and nails may also be discolored. Ochronotic arthropathy occurs last of all which is heralded by pain, stiffness and some limitation of motion of the hips, knees and shoulders. Ankylosis of the lumbosacral spine is a common late manifestation.

Diagnosis in the present case was made by the presence of the triad of degenerative arthritis, ochronotic pigmentation and urine which turns black upon alkalisation.

References

1Garrod AE. The incidence of alkaptonuria: a study in clinical individuality. Lancet 1908; ii: 73-79.
2Seymour CA. Metabolic and nutritional disorders. In: Textbook of Dermatology Champion RH, Burton JL, Burns DA, et al 6th edn. London. Blackwell Scientific Publications, 1998; 2648.
3Srsen S, Cisarik F, Paszter L, et al. Alkaptonuria in Trencin district of Czechoslovakia. Am 3 Med Genet 1978; 2: 159-166.
4Pollak MR, Chou Y-HW, Cerda JJ, et al. Homozygosity mapping of the gene for alkaptonuria to chromosome 3q2. Nat Genet 1993; 5: 201-204.
5Fernandez-Canon JM, Grenadine B, Beltron Valero de Barnacle D, et al. The molecular basis of alkaptonuria. Nature Genet 1996; 14: 19-24.
6Felbon U, Mutsch Y, Grehn F Ocular ochronosis in alkaptonuria patients carrying mutation in the homogentisate 1,2 dioxygenase gene. Br J Opthalmol 1999;83: 680-683.

 

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