Treatment Of Ornithine Transcarbamylase Deficiency Research Articles

Treatment of ornithine transcarbamylase deficiency in a child with glyceryl phenylbutyrate

Glyceryl phenylbutyrate (GPB) serves as a long-term management medication for Ornithine transcarbamylase deficiency (OTCD), effectively controlling hyperammonemia, but there is a lack of experience in using this medicine in China. This article retrospectively analyzes the case of a child diagnosed with OTCD at Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, including a review of related literature. After diagnosis, the patient was treated with GPB, followed by efficacy follow-up and pharmacological monitoring. The 6-year and 6-month-old male patient exhibited poor speech development, disobedience, temper tantrums, and aggressive behavior. Blood ammonia levels peaked at 327 μmol/L; urine organic acid analysis indicated elevated uracil levels; cranial MRI showed extensive abnormal signals in both cerebral hemispheres. Genetic testing revealed de novo mutation in the OTC gene (c.241T>C, p.S81P). Blood ammonia levels were approximately 43, 80, and 56 μmol/L at 1, 2, and 3 months after starting GPB treatment, respectively. During treatment, blood ammonia was well-controlled without drug-related adverse effects. The patient showed improvement in developmental delays, obedience, temperament, and absence of aggressive behavior.

Characterization of an ornithine transcarbamylase conditional knockout mouse model: A novel model for understanding the effect of MRNA therapies for treatment of ornithine transcarbamylase deficiency

Characterization of an ornithine transcarbamylase conditional knockout mouse model: A novel model for understanding the effect of MRNA therapies for treatment of ornithine transcarbamylase deficiency

Consensus on diagnosis and treatment of ornithine trans-carbamylase deficiency

Ornithine transcarbamylase deficiency(OTCD)is a most common ornithine cycle (urea cycle) disorder. It is a X-link inherited disorder caused by OTC gene mutation that in turn leads to reduction or loss of OTC enzyme activity. Its onset time is related to the lack of enzyme activity. Patients with neonatal onset usually have complete absence of OTC enzyme activity, which is mainly associated with male semi-zygotic mutations; and the disease progresses rapidly with high mortality rates. Patients with late onset vary in onset age and clinical manifestations, and the course of disease can be progressive or intermittent. The acute attack mainly manifests neuropsychiatric symptoms accompanied by digestive symptoms like liver function damage or even acute liver failure. Elevated blood ammonia is the main biochemical indicator of OTCD patients. Increased glutamine, decreased citrulline in blood, and increased orotic acid in urine are typical clinical manifestations for OTCD patients. Genetic testing of OTC gene is important for OTCD diagnosis. The goal of treatment is to minimize the neurological damage caused by hyperammonemia while ensuring the nutritional needs for patient development. For patients with poor response to medication and diet, liver transplantation is recommended under the condition of stable metabolic state and absence of severe neurological damage. During long-term treatment, physical growth indicators, nutrition status, liver function, blood ammonia and amino acids should be regularly monitored. This consensus aims to standardize the diagnosis and treatment of OTCD, improve the prognosis, reduce the mortality and disability of patients.

Orphan designation: Sodium benzoate,Sodium phenylacetate, Treatment of ornithine transcarbamylase deficiency

Orphan designation: Sodium benzoate,Sodium phenylacetate, Treatment of ornithine transcarbamylase deficiency

416. Optimization of the Expression Cassette Using an AAV2/8 Based Vector for the Treatment of Ornithine Transcarbamylase Deficiency

416. Optimization of the Expression Cassette Using an AAV2/8 Based Vector for the Treatment of Ornithine Transcarbamylase Deficiency

Living donor liver transplantation: issues regarding left liver grafts

The necessity of widening the indications for living donor liver transplantation (LDLT) has been emphasised. Clarification of the advantages and limitations of using a left liver graft for LDLT in adults is essential for donor safety. Between June 1990 and November 2002, 185 patients underwent LDLT at Shinshu University Hospital, Japan. In 97 of these, the graft comprised the left liver with or without the left portion of the caudate lobe. The peri-hepatectomy profiles of the donors, significance of left liver grafts, postoperative courses of the donors and recipients, and survival of the recipients were investigated. All the donors recovered well and returned to a normal lifestyle. None required banked-blood transfusion or repeat surgery, and postoperative liver function tests had satisfactory results. The cold ischaemic time for the graft was 127+/-54 minutes. The graft volumes (GVs) ranged from 230 to 625 ml, and GV/standard liver volume (SV) ratios varied from 22% to 65%, at the time of transplantation. Although 85% of the liver grafts had GV/SV ratios <50%, no patient developed immediate postoperative liver failure. Patient survival rates were 89%, 84% and 84% at 1, 3 and 5 years, respectively. Although LDLT using a left liver graft imposes potential postoperative complications (a small liver is more vulnerable to injury, and recipients of small grafts are at higher risk of complications during recovery), such grafts have yielded acceptable results in adult LDLT, with minimal burden to the donors.

Introduction

Introduction

Lawsuits against IRBs: accountability or incongruity?

Pressure is mounting to hold researchers and research institutions accountable for the protection of human subjects. When subjects or their family members believe they have been injured, they are increasingly willing to file lawsuits. Recent cases indicate that institutional review boards (IREs) and their members may be pulled more and more into the legal fray.On September 17, 1999, 18-year-old Jesse Gelsinger died while participating in research conducted by the University of Pennsylvania's Institute for Gene Therapy. Gelsinger was involved in a Phase I clinical trial testing a new approach to treatment of ornithine transcarbamylase deficiency (OTC), a rare metabolic disorder. Although infants affected by the severe form of OTC die shortly after birth, Gelsinger suffered from a relatively mild form. It appears undisputed that the cause of Gelsinger's death was not the disorder itself, but multiple organ system failure triggered by the virus used to carry new genetic material into his system.

Expression of wild-type and mutant human ornithine transcarbamylase genes in Chinese hamster ovary cells and lack of dominant negative effect of R141Q and R40H mutants.

Chinese hamster ovary cultured cells were transformed to continuously express wild-type and two mutant ornithine transcarbamylase genes, R141Q and R40H. In addition, these cells were transfected to transiently express the same genes. The R141Q mutation abolishes the enzymatic activity, and the amount of "mature" protein present in transfected cells is equivalent to the wild type. The R40H mutation causes a reduction of enzymatic activity to approximately 26 to 35% of wild type concomitant with a significant reduction in the amount of protein present. Transfection with wild-type and mutant genes together in various proportions did not reveal dominant negative effects of the two mutations studied. This expression system can be used to examine the deleterious effect of private mutations or lack thereof in families with ornithine transcarbamylase deficiency as well as evaluate the potential dominant negative effects of gene delivery for treatment of ornithine transcarbamylase deficiency.

Treatment of ornithine transcarbamylase deficiency in girls by auxiliary liver transplantation: Conceptual changes in a living-donor program

Background/Purpose: Ornithine transcarbamylase (OTC) deficiency is an X-chromosome-linked genetic disorder resulting in hyperammonemia hepatic dysfunction, coma, and serious neurological sequelae. This report describes an experience in treating this condition with living-related liver transplantation. Methods: Three children with OTC were treated with a living-related liver transplantation. Potential donors were evaluated with the allopurinol loading test to exclude heterozygotes. FK506 and low-dose steroids were used for immunosuppression. Auxiliary partial orthotopic transplantation (APOLT) was used in two of the cases. Results: All three children survived and are doing well without protein restriction. Conclusions: These observations suggest that in OTC removal of the native liver is not necessary because (1) a partial liver segment with normal enzyme activity corrects the hyperammonemia, (2) in case of graft failure the native liver is an available backup, and (3) the native liver has the ability to recover function. As long as living-related donors serve as the main source of donor organs, APOLT is a safer approach to liver transplantation in OTC.

Vomiting, ataxia, and altered mental status in an adolescent: Late-onset ornithine transcarbamylase deficiency

A case of a 13-year-old boy with protracted vomiting, ataxia, and altered mental status, ultimately diagnosed with late-onset ornithine transcarbamylase (OTC) deficiency, is presented. OTC deficiency is the most common urea cycle defect and typically is diagnosed in male infants with irritability, poor feeding, vomiting, lethargy, and often death caused by the effects of hyperammonemia. Late-onset OTC deficiency has been described in patients of all ages. The presenting symptoms in these patients vary but the most common are vomiting and lethargy. The pathophysiology, clinical features, differential diagnosis, and treatment of this disorder are discussed. Because of the risks of serious consequences, early detection and treatment of OTC deficiency and hyperammonemic episodes are mandatory. Emergency physicians caring for children and adults need to be aware of the spectrum of clinical presentation of OTC deficiency, including late-onset disease.