Richner–Hanhart Syndrome (Tyrosinemia II): Early Diagnosis of an Incomplete Presentation with Unusual Findings

Viglizzo, G.; Occella, C.; Bleidl, D.; Rongioletti, Franco

doi:10.1111/j.1525-1470.2006.00230.x

Cited by 17 publications

(12 citation statements)

References 8 publications

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“…These lesions are typically present on both palms and soles except in cases 63 and 114, who only had affected soles, and there was an unusual presentation with vesicular lesions in the fingertips (Id. 110) …”

Section: Resultsmentioning

confidence: 99%

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Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation

et al. 2017

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Section: Resultsmentioning

confidence: 99%

“…110). 38 Only 2 cases presented with severe mental retardation: One patient (Id. 57) had an inherited TAT deletion of 50 kb plus a de novo large chromosomal deletion spanning the TAT locus, who in addition suffers from multiple congenital anomalies, 17,18 while the other patient (Id.…”

Section: Rhs Mutation Update At the Tat Locusmentioning

confidence: 99%

Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation

et al. 2017

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“…Skin lesions consist of painful hyperkeratotic plaques of soles and palms (8,9). The fingertips and the hypothenar and thenar eminences are areas of predilection (10).…”

Section: Discussionmentioning

confidence: 99%

Richner–Hanhart Syndrome Detected by Expanded Newborn Screening

Meißner

Betz

Pasternack

et al. 2008

Pediatric Dermatology

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Richner-Hanhart syndrome (tyrosinemia type 2) is an inborn error of tyrosine metabolism which is clinically characterized mainly by oculocutaneous symptoms including corneal opacities and keratosis palmoplantaris. Skin symptoms usually develop after the first year of life. We report a neonate in whom already on the third day of life diagnosis of Richner-Hanhart syndrome could be suspected because of elevated tyrosine levels in newborn screening by tandem mass spectrometry. Analysis of the tyrosine aminotransferase gene revealed a homozygous missense mutation p.R433W (c.1297C>T). An 8-year-old brother with persistent plantar hyperkeratotic plaques of the soles of yet unknown origin was subsequently identified to be also affected with Richner-Hanhart syndrome. This demonstrates that early diagnosis of Richner-Hanhart syndrome is possible in neonates by extended newborn screening. Early introduction of dietary treatment is a prerequisite to reduce the risk of clinical symptoms.

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“…To our knowledge, the actual concentration that is reached into the brain of type II patients is not known. It was reported that plasma tyrosine levels may exceed 1000 μM in untreated type II patients (Scott, 2006), but other studies found that plasma tyrosine values range from 370 to 3420 μM (Goldsmith et al, 1973; Lemonnier et al, 1979; Rabinowitz et al, 1995; Mitchell et al, 2001; Macsai et al, 2001; Viglizzo et al, 2006). Although some effects presented here may have pathophysiological relevance to tyrosinemia type II, we cannot rule out that these effects were suprapathological.…”

Section: Methodsmentioning

confidence: 99%

Tyrosine promotes oxidative stress in cerebral cortex of young rats

Sgaravatti

Vargas

Zandoná

et al. 2008

Intl J of Devlp Neuroscience

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Tyrosine accumulates in inborn errors of tyrosine catabolism, especially in tyrosinemia type II, where tyrosine levels are highly elevated in tissues and physiological fluids of affected patients. In tyrosinemia type II, high levels of tyrosine are correlated with eyes, skin and central nervous system disturbances. Considering that the mechanisms of brain damage in these disorders are poorly known, in the present study, we investigated whether oxidative stress is elicited by l-tyrosine in cerebral cortex homogenates of 14-day-old Wistar rats. The in vitro effect of 0.1-4.0mM l-tyrosine was studied on the following oxidative stress parameters: total radical-trapping antioxidant potential (TRAP), total antioxidant reactivity (TAR), ascorbic acid content, reduced glutathione (GSH) content, spontaneous chemiluminescence, thiobarbituric acid-reactive substances (TBA-RS), thiol-disulfide redox state (SH/SS ratio), protein carbonyl content, formation of DNA-protein cross-links, and the activities of the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glucose-6-phosphate dehydrogenase (G6PDH). TRAP, TAR, ascorbic acid content, SH/SS ratio and CAT activity were significantly diminished, while formation of DNA-protein cross-link was significantly enhanced by l-tyrosine in vitro. In contrast, l-tyrosine did not affect the other parameters of oxidative stress evaluated. These results indicate that l-tyrosine decreases enzymatic and non-enzymatic antioxidant defenses, changes the redox state and stimulates DNA damage in cerebral cortex of young rats in vitro. This suggests that oxidative stress may represent a pathophysiological mechanism in tyrosinemic patients, in which this amino acid accumulates.

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Richner–Hanhart Syndrome (Tyrosinemia II): Early Diagnosis of an Incomplete Presentation with Unusual Findings

Cited by 17 publications

References 8 publications

Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation

Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation

Richner–Hanhart Syndrome Detected by Expanded Newborn Screening

Tyrosine promotes oxidative stress in cerebral cortex of young rats

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