Alkaptonuria (also known as AKU) is a rare and debilitating metabolic disorder affecting cartilaginous tissue in the joints. It is inherited in an autosomal, recessive manner and patients with this disorder have a mutation in both copies of the gene that codes for the enzyme, homogentisate 1, 2-dioxygenase, or HGD.
As a result, the dysfunctional enzyme cannot break down an intermediary product in the metabolism of amino acid tyrosine which is present in almost all protein-rich foods.
This intermediary product, a pigment called homogentisic acid or HGA, builds up in the cartilage of joints and vertebral discs. Over time, the cartilage becomes brittle and begins to break down, leading to arthritis in the joints, mostly discs in the spine, hips, knee, ankles and shoulders.
Mobility and range of movement are greatly reduced in these joints, the symptoms usually accompanied by significant pain. Another site of deposit of HGA is the mitral valve in the heart causing calcification and reduced valve function.
According to a release from Sumita Danda, professor and Head of the Department of Clinical Genetics, Christian Medical College, Vellore, AKU is common in the country in certain populations that practice endogamy or marriage within the community, such as Narikuravas or Vagiriyars, a sub-group of the Romanis in India.
More than 1,000 AKU sufferers are estimated to be in India alone, with many more still undiagnosed owing to lack of awareness among patients and physicians.
Without greater awareness of this painful disorder, a cure may not be developed in time to help thousands of young children who have been born with AKU .
In order to address this shortfall, the Departments of Clinical Genetics, Rheumatology and Orthopaedic Surgery of CMC have arranged a workshop on September 21. Nick Sireau, CEO and Chairman of the AKU Society, Europe, would inaugurate the Indian chapter of AKU Society, which would look to raise awareness of AKU within the country for the purpose of better diagnosis and fund-raising for research and the development of a cure.
Clinical Genetics Department would also host an international symposium on Lysosomal Storage Disorders (LSD), which is a group of genetic disorders caused by lack of specific enzymes in the body leading to deposition of toxic metabolites in vital body organs.
These disorders are now in the limelight of the medical field with development of newer therapies based on enzyme replacement.