Hereditary Tyrosinemia of Chronic Course without Rickets and Renal Tubular Dysfunction

ABSTRACT. Three patients with hereditary tyrosinemia type 1, two brothers and one girl, studied at the age of 5, 12 and 15 years, respectively, had neither generalized hyperaminoaciduria, glucosuria nor clinical symptoms of rickets. Untreated the elder brother had only slightly elevated plasma tyrosine level (141 μmol/l, normal <80), and low excretion of p-hydroxyphenyllactate. He presented with pronounced thrombocytopenia (3 × 10⁹/1). At 13 years of age he contracted hepatocellular carcinoma. The younger brother presented with serum tyrosine of 318 μol/l and thrombocyte count 48 × 10⁹/1. Succinylacetone in urine was elevated in both, 30 and 79 μmol/mmol creatinine, respectively. The female patient was investigated for hepatomegaly in infancy, atypical tyrosinemia being considered, but afterwards developed normally without diet or any other treatment until she contracted hepatoma at the age of 15 years. Her plasma tyrosine level was 600-700 μmol/1, and she excreted large amounts of p-hydroxyphenyllactate. Succinylacetone in urine was low but elevated (8 μmol/mmol creatinine). The fumarylacetoacetase activity in fibroblasts from the brothers and in lymphocytes from the girl was less than 5% and 10% of control levels, respectively. In conclusion, the chronic form of hereditary tyrosinemia may occur without evidence of renal tubular dysfunction.     

Experience of a Single Center in NTBC Use in Management of Hereditary Tyrosinemia Type I in Libya

Background:

Hereditary Tyrosinemia type I (HTI) is a metabolic disease caused by deficiency of fumarylacetoacetate hydrolase enzyme.

Objectives:

This study reports beside its clinical and biochemical presentation, the outcome of NTBC [2- (2-nitro-4-trifloro-methylbenzoyl)-1, 3-cyclohexanedion] treatment of the disease and evaluates its biochemical markers in 16 pediatric Libyan patients.

Patients and Methods:

The diagnosis was based on presence of high tyrosine levels in blood and succinylacetone in urine.

Results:

The consanguinity rate was 81.2%, the median age at onset, at diagnosis and at starting treatment were 4.5, 8, and 9.5 months respectively. At presentation hepatomegaly, jaundice, rickets and high gamma glutamyl transferase (GGT) were observed in 87.5% of patients. All patients had extremely high alpha fetoprotein (AFP) and high alkaline phosphatase (ALP) levels. Fifteen patients were treated with NTBC, normalization of PT (Prothrombine time) was achieved in average in 14 days. The other biochemical parameters of liver function (transaminases, GGT, ALP, bilirubin and albumin) took longer to improve and several months to be normalized. Survival rate with NTBC was 86.6%. Patients who started treatment in a median of 3 months post onset observed a fast drop of AFP in 90.6% of patients (P = 0.003). Abnormal liver function and rickets were the common presentations, GGT was an early cholestatic sensitive test. ALP was constantly high even in asymptomatic patients.

Conclusions:

In HT1 a faster dropping of AFP is a marker of good prognosis.     

Tyrosinemia: A Review

Hypertyrosinemia encompasses several entities, of which tyrosinemia type I (or hepatorenal tyrosinemia, HT1) results in the most extensive clinical and pathological manifestations involving mainly the liver, kidney, and peripheral nerves. The clinical findings range from a severe hepatopathy of early infancy to chronic liver disease and rickets in the older child; gradual refinements in the diagnosis and medical management of this disorder have greatly altered its natural course, mirroring recent advances in the field of metabolic diseases in the past quarter century. Hepatorenal tyrosinemia is the inborn error with the highest incidence of progression to hepatocellular carcinoma, likely due to profound mutagenic effects and influences on the cell cycle by accumulated metabolites. The appropriate follow-up of patients with cirrhosis, the proper timing of liver transplantation in the prevention of carcinoma, and the long-term evolution of chronic renal disease remain important unresolved issues. The introduction of a new pharmacologic agent, NTBC, holds the hope of significantly alleviating some of the burdens of this disease. Mouse models of this disease have permitted the exploration of newer treatment modalities, such as gene therapy by viral vectors, including ex vivo and in utero methods. Finally, recent observations on spontaneous genetic reversion of the mutation in HT1 livers challenge conventional concepts in human genetics. Received November 15, 2000; accepted December 7, 2000.     

婴幼儿先天性胸腹裂孔疝的手术治疗

目的探讨婴幼儿先天性胸腹裂孔疝的治疗方法，提高生存率。方法回顾我院1986～2003年收治16h-2岁先天性胸腹裂孔疝53例的手术治疗，其中5例经胸手术，48例经腹手术。结果治愈47例，死亡6例。随访30例2月-10年。X线透视肺膨胀良好，术后早期体重增加，呼吸道感染明显减少。结论提高诊断、急救技术，完善新生儿围手术期措施，可提高婴幼儿先天性胸腹裂孔疝的生存率。     

Tyrosinemia type III: diagnosis and ten-year follow-up

Tyrosinemia type III, caused by deficiency of 4-hydroxyphenylpyruvate dioxygenase, is a rare disorder of tyrosine catabolism. Primary 4-hydroxyphenylpyruvate dioxygenase deficiency has been described in only three patients. The biochemical phenotype shows hypertyrosinemia and elevated urinary excretion of 4-hydroxyphenyl derivatives. We report the clinical and biochemical findings and the results of long-term follow-up in a new patient with this disorder presenting with severe mental retardation and neurological abnormalities. The clinical phenotype is compared with those reported in the three previously described patients.     

Tyrosinemia type I: A clinico-laboratory case report

Progressive hepatocellular dysfunction in a neonate, resulting in elevated serum α-fetoprotein together with raised blood levels of tyrosine and methionine, a generalized amino aciduria and the absence of urinary δ-aminolevulinic acid and succinylacetone, suggests a diagnosis of tyrosinemia type Ib. Classical tyrosinemia type I arises from a deficiency of fumarylacetoacetate hydrolase while the variant tyrosinemia type Ib results from a deficiency of maleylacetoacetate isomerase.     

Tyrosinemia associated with perinatal infection with cytomegalovirus.

A premature infant presented with elevated concentrations of tyrosine in blood and urine, evidence of hepatocellular damage, demineralization of the bones, and a renal Fanconi syndrome. This is the clinical picture found in hereditary tyrosinemia. The infant also had a perinatal infection with cytomegalovirus.     

Tyrosinemia type 1 in pediatric nephrology: Not always straightforward

The main clinical features of tyrosinemia type 1 usually appear in the first months of life, including fever, diarrhea, vomiting, liver involvement, growth failure, and renal proximal tubulopathy with subsequent hypophosphatemic rickets. An early diagnosis is crucial in order to provide specific management and to prevent complications. Here, we report on two cases referred primarily to pediatric nephrologists for the diagnosis of “neonatal tubulopathy” and management of “X-linked hypophosphatemia (XLH),” respectively. Our aim is to emphasize that (1) even a mixed tubulopathy can reveal tyrosinemia, and (2) tyrosinemia is a classic differential diagnosis of XLH that should not be forgotten, especially in the era of the anti-FGF23 burosumab.     

遗传相关性低镁血症

镁离子在体内参与多种生化代谢反应,对各器官系统发挥正常生理功能起重要作用.体内镁离子的平衡主要依赖于肠道镁吸收和肾脏镁排泄的精密调节.遗传性低镁血症包括家族性低镁血症合并高尿钙和肾钙质沉着、常染色体显性遗传低镁血症合并低尿钙、家族性低镁血症继发低钙血症、常染色体显性遗传低钙血症等.近年来,对于这些遗传性低镁血症的基因研究及相关蛋白质功能研究使人们对体内镁离子转运机制有了更深一步的认识.