There is a 25% risk of having a child with the disorder, when both parents are carriers of an autosomal recessive trait. Cystinosis affects approximately 1 in 100,000 to 200,000 newborns. and there are only around 2,000 known individuals with cystinosis in the world. The incidence is higher in the province of Brittany, France, where the disorder affects 1 in 26,000 individuals. Diagnosis
Cystinosis is a rare genetic disorder that causes an accumulation of the amino acid cystine within cells, forming crystals that can build up and damage the cells. These crystals negatively affect many systems in the body, especially the kidneys and eyes.The accumulation is caused by abnormal transport of cystine from lysosomes, resulting in a massive intra-lysosomal cystine accumulation in tissues. Via an as yet unknown mechanism, lysosomal cystine appears to amplify and alter apoptosis in such a way that cells die inappropriately, leading to loss of renal epithelial cells. This results in renal Fanconi syndrome, and similar loss in other tissues can account for the short stature, retinopathy, and other features of the disease. Definitive diagnosis and treatment monitoring are most often performed through measurement of white blood cell cystine level using tandem mass spectrometry. Types
Online Mendelian Inheritance in Man (OMIM): 219800 – Infantile nephropathic
Online Mendelian Inheritance in Man (OMIM): 219900 – Adolescent nephropathic
Online Mendelian Inheritance in Man (OMIM): 219750 – Adult nonnephropathic

Treatment
Cystinosis is normally treated with cysteamine, which is available in capsules and in eye drops.
He linked ochronosis with the accumulation of alkaptans in 1902, and his views on the subject, including its mode of heritance, were summarized in a 1908 Croonian Lecture at the Royal College of Physicians. The genetics of it was also studied by William Bateson in the 1902.The defect was narrowed down to homogentisic acid oxidase deficiency in a study published in 1958. The genetic basis was elucidated in 1996, when HGD mutations were demonstrated.A 1977 study showed that an ochronotic Egyptian mummy had probably suffered from alkaptonuria. Research directions
Research collaborations by several national centres have been established to find a more definitive treatment for alkaptonuria. This has included studies on the use of nitisinone and investigations into antioxidants to inhibit ochronosis. The ideal treatment would replace HGD enzyme function without accumulating other substances. See also
List of cutaneous conditions
List of radiographic findings associated with cutaneous conditions

References


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