Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Articles published during the past year on the ocular manifestations of metabolic diseases and related issues are reviewed. The focus is on clarifying the genetic or molecular basis of various metabolic disorders. Mutations of the P gene were reported in tyrosinase-positive oculocutaneous albinism and autosomal recessive ocular albinism, and were associated with a wide range of clinical phenotypes. This finding should aid in more accurate diagnosis and facilitate genetic counseling. There is no consensus but the horizontal supranuclear gaze palsy in Gaucher's disease may aid in subtyping. The report of a family with Morquio syndrome suggests that lenticular opacities should be considered as an additional finding in this syndrome. Patients with nephropathic cystinosis, which had been a fatal disease in childhood, are now surviving to adulthood. Serious ocular complications were described in adults.
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PMID:Ocular manifestations of metabolic disorders. 1015 Aug 32

Cystinosis is a rare autosomal recessive disease characterized by cystine crystal accumulation leading to multiorgan dysfunctions and caused by mutation in CTNS. CTNS encodes cystinosin, a cystine/H(+) symporter that exports cystine out of the lysosomes. Patients with cystinosis frequently exhibit blond hair and fair complexion, suggesting an alteration in melanogenesis. However, the pigmentation singularities of these patients have not been studied, and the role of cystinosin in melanogenesis has remained unknown. In our study, a clinical evaluation of 27 patients with cystinosis showed that 44% had a cutaneous pigmentation dilution compared to their relatives. Analysis of the hair melanin content in these patients by HPLC demonstrated a 50% decrease in eumelanin (4360 vs. 9360 ng/mg), and a 2-fold increase in pheomelanin (53 vs. 20 ng/mg), the yellow/red pigments. Cystinosin-deficient mice also showed a 4-fold increase in hair pheomelanin content. In vitro studies showed that cystinosin was located at melanosomes. CTNS silencing led to a 75% reduction of melanin synthesis that was caused by a degradation of tyrosinase by lysosomal proteases. Our results objectify the pigmentation defect in patients with cystinosis. We also identify the role of CTNS in melanogenesis and add a new gene to the list of the genes involved in the control of skin and hair pigmentation.
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PMID:Cystinosin is a melanosomal protein that regulates melanin synthesis. 2264 30