Alkaptonuria aka black urine disease

Hi brainy folks, Alkaptonuria is also called black urine disease and this feature is present from birth. Over time child develops other signs and symptoms.

Alkaptonuria is autosomal recessive inborn error of protein metabolism which affects phenylalanine and tyrosine degradation pathway.

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It results from absence of enzyme HGD (Homogentisate 1,2 dioxygenase), defect of which causes accumulation of HGA (Homogentisic acid).

HGA loves collagen and accumulates wherever its is found like cartilage, skin and joints. With accumulation it causes skin pigmentation, and cartilage and joint damage. Accumulation has specific name called Ochronosis. The name is given because of its yellowish brown (Ochre) pigmented appearance on microscopy.

Ochronotic Arthropathy is joint damage of knee, hip and spine with gradual accumulation of HGA.

Dark urine is very significant finding and presents since birth this is very interesting video about alkaptonuria https://youtu.be/nuVn7QGkv-I

Please share with fellow Medico-Humans 😍

Further reading https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3978898/

Revision day for cystinuria https://creativemeddoses.com/topics-list/cystinuria/