Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A deficiency of hepatic tyrosine aminotransferase in humans is responsible for a syndrome of keratitis, palmar and plantar erosions and hyperkeratosis and mental retardation. Serum tyrosine increases due to the enzymatic deficiency leads to the deposition of tyrosine crystals in the eye and cornea. This deposition and possible lysosomal activation leads to inflammation in the cornea and the skin. The syndrome can be reproduced in animals who are fed a high tyrosine diet. The interaction of tyrosine crystals with membrane-bound particles can be studied in vitro with lysosomes and erythrocytes.
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PMID:Molecular biology and molecular pathology of a newly described molecular disease--tyrosinemia II (the Richner-Hanhart syndrome). 2 31

Tyrosine-induced eye and skin lesions in man are an autosomal, recessive, inherited syndrome associated with tyrosinemia, tyrosinuria, and increased urinary excretion of tyrosine metabolites. Patients have mild to severe keratitis and erosive and hyperkeratotic lesions on the palms and soles. The degree of involvement was variable in the small number of patients studied. Mental retardation is frequently a part of the syndrome. A low-tyrosine low-phenylalanine diet lowers blood tyrosine level and leads to healing of the skin and eye lesions. Early dietary treatment may prevent mental retardation.
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PMID:Tyrosine-induced eye and skin lesions. A treatable genetic disease. 13 41

Tyrosinemia type II (Richner-Hanhart syndrome, RHS) is a disease of autosomal recessive inheritance characterized by keratitis, palmoplantar hyperkeratosis, mental retardation, and elevated blood tyrosine levels. The disease results from deficiency in hepatic tyrosine aminotransferase (TAT; L-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5), a 454-amino acid protein encoded by a gene with 12 exons. To identify the causative mutations in five TAT alleles cloned from three RHS patients, chimeric genes constructed from normal and mutant TAT alleles were tested in directing TAT activity in a transient expression assay. DNA sequence analysis of the regions identified as nonfunctional revealed six different point mutations. Three RHS alleles have nonsense mutations at codons 57, 223, and 417, respectively. One "complex" RHS allele carries a GT----GG splice donor mutation in intron 8 together with a Gly----Val substitution at amino acid 362. A new splice acceptor site in intron 2 of the fifth RHS allele leads to a shift in reading frame.
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PMID:Point mutations in the tyrosine aminotransferase gene in tyrosinemia type II. 135 62

Type II tyrosinemia (Richner-Hanhart syndrome) is a familial aminoacid disorder, clinically characterized by ocular changes (keratitis), palmo-plantar hyperkeratosis, no constant mental changes with mental deterioration, abnormal urinary excretion and high serum tyrosine level in consequence of the absence of tyrosine-aminotransferase. Almost 20 families have been described in the literature of which 50% are of Italian origin, suggesting that this disorder is particularly frequent in our country. We report a family with 2 affected members with typical clinical and biochemical findings (keratitis, palmo-plantar hyperkeratosis, abnormal urinary and serum tyrosine concentrations), not suffering from mental retardation. Clinical symptoms completely disappeared after the decrease of urinary and serum tyrosine levels following a tyrosine- and phenylalanine-free diet. These cases are compared with those reported in literature, and the usefulness of diet for the improvement of clinical and metabolic symptoms is discussed.
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PMID:The effect of diet on the ophthalmological, clinical and biochemical aspects of Richner-Hanhart syndrome: a morphological ultrastructural study of the cornea and the conjunctiva. 365 59

The Richner-Hanhart syndrome corresponds to a tyrosine elevation in serum due to deficit in soluble tyrosine aminotransferase in liver cells. This new enzymopathy which is transmitted in an autosomal recessive mode is called oculocutaneous tyrosinosis. It is curable by a poor diet in tyrosine and its precursors. The diagnosis has been invoked in a 18 months old girl, on the association of punctuate palmar and plantar keratosis, dentritic ulcerated keratitis, and mental retardation. The diagnosis is confirmed by elevation of tyrosinemia to 52 mgs/100 mls associated with a high urinary elimination of tyrosine and plenylcetonic acid. Absences of anomaly in the metabolism of methionin and hepatorenal absence of disturbance of hepatorenal system is characteristic. The keratosis accompany orthokeratotic hyperkeratosis. The keratinocytes show 2 types of anomaly ranged in strates in the epiderm. Intracytoplasmic vacuoles which include or lead to pseudomyelinic formations extend progressively from the mitochondrial alterations in the epidemial basal layers. Bulky polyhedral electron dense particles are found in the cytoplasm of the superficial keratinocytes. Most of these aspects have been demonstrated anteriorly in the keratinocytes and the cornea; on the other hand, signs of mitochondrial sulferance had not been observed. The genesis of these cellular alterations based on the liberation of lysosomial enzymes by the action of crystals of tyrosine has been suggested by Goldsmith from experimental facts. However, it seems the mitochondrial defect occurs outside this mechanism.
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PMID:[Oculo-cutaneous tyrosinosis (Richner-Hanhart syndrome). Histo-pathological study of a case]. 611 39

Three children (6 eyes) with systemic tyrosinemia who presented with a diagnosis of herpes simplex keratitis are described. Two of the patients underwent extensive treatment for herpes simplex keratitis until their defects in tyrosine metabolism were discovered. All three children responded favorably to a low-tyrosine diet. These cases illustrate the typical corneal findings of the Richner-Hanhart syndrome (pseudodendritic keratitis, hyperkeratotic skin lesions of the palms and sole without mental retardation). The findings in these three patients were similar to those cases previously reported in the literature except none had mental retardation. The ophthalmologist confronted with a young child with bilateral dendritiform keratitis should request evaluation of the serum tyrosine levels.
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PMID:Pseudodendritic keratitis and systemic tyrosinemia. 645 71

The Richner-Hanhart syndrome corresponds to a tyrosine elevation in serum due to a defect in soluble tyrosine amino-transferase in liver cells. This new enzymopathy which is transmitted in an autosomal recessive mode is called oculo-cutaneous tyrosinosis. It is curable by a low diet in tyrosine and its precursors. The diagnosis has been clinically suggested in an 18 months old girl, by the association of punctate palmar and plantar keratosis, dendritic ulcerated keratitis, and mental retardation. The diagnosis was established by elevation of tyrosinemia up to 52 mg/100 ml associated with a high urinary elimination of tyrosine and phenylcetonic acid. Absence of anomaly in the metabolism of methionin and hepatorenal lesion is characteristic. The diagnosis was confirmed by the absence of soluble tyrosine aminotransferase in liver cells and by the effectiveness of the diet. The clinical keratosis corresponds histologically to a orthokeratotic hyperkeratosis. The keratinocytes show 2 types of anomalies ranged in the epiderm. Intracytoplasmic vacuoles which include or lead to pseudomyelinic formations extend progressively from the mitochondrial alterations in the epidemial basal layers. Bulky polyhedral electron dense particles are found in the cytoplasm of the superficial keratinocytes. Most of these images have been demonstrates anteriorly in the keratinocytes ant the corned; on the other hand, signs of mitochondrial anomaly had not been observed. The genesis of these cellular alterations based on the liberation of lysosomial enzymes by the action of crystals of tyrosine has been suggested by Goldsmith from experimental facts. However, it seems that the mitochondrial defect occurs outside this mechanism.
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PMID:[Changes in the keratinocytes in oculo-cutaneous tyrosinosis: Richner-Hanhart syndrome (author's transl)]. 723 83

Richner-Hanhart syndrome (Tyrosinemia Type II) is an autosomal recessive disorder of amino acid metabolism characterized by ocular changes, painful palmoplantar hyperkeratosis, and mental retardation. Serum tyrosine increases due to tyrosine aminotransferase deficiency resulting in the deposition of tyrosine crystals in the cornea and in corneal inflammation. Patients are often misdiagnosed as having herpes simplex keratitis. We report on a child who presented with bilateral keratitis secondary to Tyrosinemia Type II diagnosed as herpes simplex keratitis.
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PMID:Richner-Hanhart syndrome (tyrosinemia type II). Case report and literature review. 764 39

Richner-Hanhart syndrome, also called oculo-cutaneous tyrosinosis type II, is a recessive autosomal genodermatosis consecutive to a disorder of tyrosine metabolism. It presents as a varying association of palmo-plantar keratosis, bilateral keratitis and mental retardation. The authors report a new case which is atypical in that palmoplantar keratosis made a late appearance. The diagnosis was confirmed by the presence of hypertyrosinaemia, hypertyrosinuria and urinary excretion of phenolic acids, and the absence of hepato-renal lesion. Needle biopsy of the liver, which demonstrates the deficiency of soluble cytosolic tyrosine aminotransferase, is not indispensable to the diagnosis and was not performed in our patient. Treatment consisted of a dietary measure: a controlled phenylalanine and tyrosine intake to obtain a tyrosinaemia below 10 mg/100 ml. This resulted in a favourable and durable course of the oculo-cutaneous lesions. In case of isolated skin lesion, retinoids can be prescribed either alone of combined with a diet, making it less strict.
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PMID:[Oculocutaneous type II tyrosinosis]. 836 6

Tyrosinemia type II (Richner-Hanhart syndrome, RHS) is a disorder of autosomal recessive inheritance characterized by keratitis, palmoplantar hyperkeratosis, mental retardation, and elevated blood tyrosine levels. The disease results from deficiency in hepatic tyrosine aminotransferase (TAT). We have previously described one deletion and six different point mutations in four RHS patients. We have now analyzed the TAT genes in a further seven unrelated RHS families from Italy, France, the United Kingdom, and the United States. We have established PCR conditions for the amplification of all twelve TAT exons and have screened the products for mutations by direct sequence analysis or by first performing single-strand conformation polymorphism analysis. We have thus identified the presumably pathological mutations in eight RHS alleles, including two nonsense mutations (R57X, E411X) and four amino acid substitutions (R119W, L201R, R433Q, R433W). Only the R57X mutation, which was found in one Scottish and two Italian families, has been previously reported in another Italian family. Haplotype analysis indicates that this mutation, which involves a CpG dinucleotide hot spot, has a common origin in the three Italian families but arose independently in the Scottish family. Two polymorphisms have also been detected, viz., a protein polymorphism, P15S, and a silent substitution S103S (TCG-->TCA). Expression of R433Q and R433W demonstrate reduced activity of the mutant proteins. In all, twelve different TAT gene mutations have now been identified in tyrosinemia type II.
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PMID:Novel and recurrent tyrosine aminotransferase gene mutations in tyrosinemia type II. 954 43


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