Peripartum management of two parturients with ornithine transcarbamylase deficiency

Two pregnancies of an ornithine carbamoyltransferase deficiency disease carrier and review of the literature

BACKGROUND

the underlying cause of the deficiency of ornithine carbamoyltransferase (OTCD) is a gene mutation on the X chromosome. In females, the phenotype is highly variable, ranging from asymptomatic to neurologic compromise secondary to hyperammonemia and it can be prompted by numerous triggers, including pregnancy.

OBJECTIVE

the objective of this article is to report a case of two pregnancies of an OTCD-carrier, and to review the literature describing OTCD and pregnancy, parturition and postpartum.

METHODS

an extensive search in PubMed in December 2021 was conducted using different search terms. After screening all abstracts, 23 papers that corresponded to our inclusion criteria were identified.

RESULTS

the article focuses on the management of OTCD during pregnancy, parturition, and the postpartum period in terms of clinical presentation, ammonia levels and treatment.

CONCLUSIONS

females with OTCD can certainly plan a pregnancy, but they need a careful management during delivery and particularly during the immediate postpartum period. If possible, a multidisciplinary team of physicians, dietitians, obstetrician-gynecologist, neonatologists, pharmacists, etc. with expertise in this field should participate in the care of women with OTCD and their children during this period and in their adult life.

Considerations for prenatal and postpartum management of a female patient with ornithine transcarbamylase deficiency

We report on pregnancy management and outcomes in a 27-year-old female patient with ornithine transcarbamylase (OTC) deficiency, the most common inherited enzyme deficiency in the urea cycle. Our patient was diagnosed during childhood after hyperammonemia associated with surgery and steroid treatment and was well-controlled with nitrogen scavenger treatment, low-protein diet, and L-citrulline supplementation. OTC gene sequencing identified a variant of unknown significance that has more recently been classified as likely pathogenic. Women with OTC deficiency are at increased risk of hyperammonemia during pregnancy and the postpartum period, therefore monthly follow up and laboratory assessments are critical in management decision making. Our patient was maintained on glycerol phenylbutyrate, L-citrulline and essential amino acid supplements, along with restricted protein intake during pregnancy. A multidisciplinary approach with the obstetrics, prenatal genetics, high risk obstetric, and anesthesia teams was also necessary for optimal management during pregnancy, throughout labor and delivery, and during the postpartum period. After successful childbirth and discharge, our patient experienced a hyperammonemic crisis related to poor enteral nutrition, and acute management protocols were implemented to stabilize her. For her newborn son, acute hyperammonemia protocols were on standby, and newborn screening and laboratory testing were expedited to assess his risk. He was healthy and did not experience symptoms of concern. In this case report, we emphasize the importance of close collaboration with maternal-fetal medicine team members during and immediately after pregnancy to ensure successful management of a female patient with OTC deficiency and her newborn.

Placental Pathology in Maternal Ornithine Transcarbamylase Deficiency

INTRODUCTION

Ornithine transcarbamylase (OTC) deficiency is the most common urea cycle disorder, inherited in an X-linked manner. Males are severely affected. Female phenotypes vary from asymptomatic to severe, and symptoms may be triggered by high metabolic states like childbirth. Literature on OTC deficiency in pregnancy and placental pathology is limited.

METHODS

Pathology records were searched at a single referral center from 2000-2020 and identified three placental cases from two mothers heterozygous for OTC deficiency. Placental pathology and maternal and neonatal history were reviewed in detail.

RESULTS

The placenta from one symptomatic mother carrying an affected male fetus showed widespread high-grade fetal vascular malperfusion (FVM) lesions of varying age. These lesions were not seen in the two placentas from the asymptomatic mother.

DISCUSSION

In cases of symptomatic maternal OTC deficiency, our findings highlight the need for placental examination. Since thrombotic events in the placenta have the potential to associate with fetal and neonatal endothelial damage, a high index of suspicion for neonatal thrombosis may be warranted.

Effect of Ornithine Transcarbamylase (OTC) Deficiency on Pregnancy and Puerperium

Ornithine transcarbamylase (OTC) deficiency is the most common inherited metabolic disorder in urea cycles with an incidence of 1:14,000 live births. Pregnancy, childbirth and the postpartum period are considered challenging for women with this hereditary metabolic disorder, with a risk of hyperammonemia, especially in the first week after delivery. In our article, we discuss severe hepatic failure, a pregnancy complication in an OTC deficient patient that has not previously been published. Firstly, our aim is to highlight the need for a strict adherence to the recommendation of the gradual increase of protein intake during pregnancy and the importance of multidisciplinary monitoring of pregnant patients with OTC deficiency. Secondly, we refer to critical postpartum hyperammonemia in patients with this hereditary metabolic disorder.

Ornithine transcarbamylase deficiency and pregnancy: A case series and review of recommendations

Background

Ornithine transcarbamylase deficiency (OTCD) is a rare disorder of the urea cycle that obstetricians should be aware of in order to guide management for pregnant carriers of the X-linked gene that causes the condition.

Cases

We present the pregnancy management and outcomes of two women with OTCD. The particular manifestations of the disease drive antenatal, intrapartum and postpartum management.

Conclusion

Preconception counseling, early prenatal diagnostics and multidisciplinary intrapartum and postpartum management plans contribute to improved outcomes for patients.

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Ornithine transcarbamylase deficiency (OTCD) is a rare X-linked genetic disorder of the urea cycle.

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Two cases of ornithine transcarbamylase deficiency in pregnancy are described.

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The antenatal, intrapartum, and postpartum management of OTCD in pregnancy is described.

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Preconception counseling, early prenatal diagnostics and multidisciplinary management plans contribute to improved outcomes for patients.

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Recognition of the condition supports the prevention of hyperammonemia.

Role of early management of hyperornithinaemia-hyperammonaemia-homocitrullinuria syndrome in pregnancy

Hyperornithinaemia-hyperammonaemia-homocitrullinuria (HHH) syndrome is a rare inherited metabolic disorder of the urea cycle. Few reports exist to guide practices during pregnancy and fetal delivery. Yet, with affected patients often surviving into reproductive age, appropriate management of the peripartum phase is essential to ensure positive maternal and fetal outcomes.

Reassuringly, the vast majority of offspring of parturients with HHH syndrome have normal developmental outcomes; yet as seen here, fetal growth restriction does appear more frequently. Furthermore, in addition to the absent fetal corpus callosum observed in this case, other fetal cerebral abnormalities, including speech delay and intellectual impairment, have been recognised.

Unregulated dietary intake is one proposed factor for the observed disruption in fetal growth and early cerebral development. These stipulations not only reinforce the importance of extensive planning and teamwork, but also demonstrate the importance of timely intervention by a metabolic dietician and dietary compliance in the early organogenesis stage of pregnancy.

Physical, cognitive, and social status of patients with urea cycle disorders in Japan

Urea cycle disorders (UCDs) are inherited metabolic diseases that lead to hyperammonemia. Severe hyperammonemia adversely affects the brain. Therefore, we conducted a nationwide study between January 2000 and March 2018 to understand the present status of UCD patients in Japan regarding diagnosis, treatments, and outcomes. A total of 229 patients with UCDs (126 patients: ornithine transcarbamylase deficiency [OTCD]; 33: carbamoyl phosphate synthetase 1 deficiency [CPS1D]; 48: argininosuccinate synthetase deficiency [ASSD]; 14: argininosuccinate lyase deficiency [ASLD]; and 8: arginase 1 deficiency [ARG1D]) were enrolled in the present study. Although growth impairment is common in patients with UCDs, we discovered that Japanese patients with UCDs were only slightly shorter than the mean height of the general adult population in Japan. Patients with neonatal-onset UCDs are more likely to experience difficulty finding employment and a spouse; however, some patients with late-onset UCDs were employed and married. Additionally, intellectual and developmental disabilities, such as attention deficit hyperactivity disorder (ADHD) and autism, hinder patients with UCDs from achieving a healthy social life. Moreover, we identified that it is vital for patients with UCDs presenting with mild to moderate intellectual disabilities to receive social support. Therefore, we believe the more robust social support system for patients with UCDs may enable them to actively participate in society.

Nutrition and medical support during pregnancy and lactation in women with inborn errors of intermediary metabolism disorders (IEMDs)

The establishment of expanded newborn screening (NBS) not only results in the early diagnosis and treatment of neonates with inborn errors of intermediary metabolism disorders (IEMDs) but also helps the affected females to reach the reproductive age under medical and dietetic support, as well as to give birth to normal infants. In this review, we aimed to focus on laboratory investigation tests, dietetic management and medical support for most known IEMD pregnant and lactating women, such as those suffering from aminoacidopathies, carbohydrate metabolic diseases and fatty acid (FAO) oxidation disorders.

Suggested guidelines for the diagnosis and management of urea cycle disorders: First revision

In 2012, we published guidelines summarizing and evaluating late 2011 evidence for diagnosis and therapy of urea cycle disorders (UCDs). With 1:35 000 estimated incidence, UCDs cause hyperammonemia of neonatal (~50%) or late onset that can lead to intellectual disability or death, even while effective therapies do exist. In the 7 years that have elapsed since the first guideline was published, abundant novel information has accumulated, experience on newborn screening for some UCDs has widened, a novel hyperammonemia-causing genetic disorder has been reported, glycerol phenylbutyrate has been introduced as a treatment, and novel promising therapeutic avenues (including gene therapy) have been opened. Several factors including the impact of the first edition of these guidelines (frequently read and quoted) may have increased awareness among health professionals and patient families. However, under-recognition and delayed diagnosis of UCDs still appear widespread. It was therefore necessary to revise the original guidelines to ensure an up-to-date frame of reference for professionals and patients as well as for awareness campaigns. This was accomplished by keeping the original spirit of providing a trans-European consensus based on robust evidence (scored with GRADE methodology), involving professionals on UCDs from nine countries in preparing this consensus. We believe this revised guideline, which has been reviewed by several societies that are involved in the management of UCDs, will have a positive impact on the outcomes of patients by establishing common standards, and spreading and harmonizing good practices. It may also promote the identification of knowledge voids to be filled by future research.

Maternal ornithine transcarbamylase deficiency, a genetic condition associated with high maternal and neonatal mortality every clinician should know: A systematic review

Ornithine transcarbamylase deficiency (OTCD) is a rare X-linked urea cycle disorder. Maternal OTCD can lead to life-threatening hyperammonemia if untreated. We aimed to compare the outcomes of maternal OTCD when diagnosis is known prior to pregnancy to when diagnosis is made during pregnancy. We performed a systematic literature review on maternal OTCD using the databases Ovid MEDLINE and PubMed from 1982 through 2018. Studies were included if addressed maternal OTCD signs, symptoms, and detailed pregnancy outcomes. We calculated the median or the mean for continuous variables and percentages for categorical variables. Of 36 cases of maternal OTCD, 20 (55%) were diagnosed prior to pregnancy while 16 (45%) were not. In the 20 patients diagnosed prior to pregnancy, 7 (35%) had either a neurologic or psychiatric presentation during pregnancy or postpartum. Two hyperammonemic patients (11%) experienced ICU admission, dialysis, and coma with no maternal deaths. All had a favorable outcome. In the 16 patients not known to have maternal OTCD prior to pregnancy, 13 (81%) had neurologic or psychiatric presentation during pregnancy or postpartum. Four presented with hyperemesis gravidarum. Eleven (69%) hyperammonemic patients had ICU admission and coma and 7 (47%) of them had dialysis. There were 5 (31%) maternal deaths. Three patients (19%) had prolonged hospitalization course. Overall, three male neonatal deaths were reported. Three other male children had liver transplant. Maternal OTCD is associated with high maternal and neonatal morbidity and mortality when diagnosis is made during pregnancy compared to when diagnosis is known prior to pregnancy.

Malnutrition with hypoaminoacidemia in a 22-year-old pregnant patient masking a likely ornithine transcarbamylase deficiency

BACKGROUND

Symptoms and clinical presentations of OTC deficiency vary widely according to the remaining activity of the enzyme. Three factors determine the residual enzyme activity. First, as the OTC gene is carried on the X chromosome, a complete inactivation of this enzyme in a newborn boy results an acute ammonia intoxication. Second, the female mosaicism due to lyonization (differential randomized X-inactivation) leads to differential OTC expression in hepatocytes. Third, the degree of severity depends on the mutation and the level of remaining activity it leaves to the protein. Published cases of OTC deficiency during pregnancy are scant. Most often, diagnosis of the metabolic disease is made before pregnancy or during the post-partum period.

METHODS

We report the case of a 22-year-old woman's successful pregnancy with a moderate form of ornithine transcarbamylase (OTC) deficiency, unsuspected before pregnancy, biochemically consistent with plasma aminoacidogram and orotic acid analysis, and initially masked by malnutrition.

RESULTS - CONCLUSION

Although maternal ammonia was subnormal and the neonate was safe, an OTC deficiency was revealed by stress factors such as the pregnancy itself and infection, and associated with uncontrollable maternal vomiting and psychiatric syndrome. However, this metabolic disease, revealed by aminoacidogram and urine orotic acid analysis, fortunately did not prevent a successful pregnancy. Even if infrequent, this situation deserves to be highlighted.

Impact of pregnancy on inborn errors of metabolism

Once based mainly in paediatrics, inborn errors of metabolism (IEM), or inherited metabolic disorders (IMD) represent a growing adult medicine specialty. Individually rare these conditions have currently, a collective estimated prevalence of >1:800. Diagnosis has improved through expanded newborn screening programs, identification of potentially affected family members and greater awareness of symptomatic presentations in adolescence and in adulthood. Better survival and reduced mortality from previously lethal and debilitating conditions means greater numbers transition to adulthood. Pregnancy, once contraindicated for many, may represent a challenging but successful outcome. Successful pregnancies are now reported in a wide range of IEM. Significant challenges remain, given the biological stresses of pregnancy, parturition and the puerperium. Known diagnoses allow preventive and pre-emptive management. Unrecognized metabolic disorders especially, remain a preventable cause of maternal and neonatal mortality and morbidity. Increased awareness of these conditions amongst all clinicians is essential to expedite diagnosis and manage appropriately. This review aims to describe normal adaptations to pregnancy and discuss how various types of IEM may be affected. Relevant translational research and clinical experience will be reviewed with practical management aspects cited. Based on current literature, the impact of maternal IEM on mother and/or foetus, as well as how foetal IEM may affect the mother, will be considered. Insights gained from these rare disorders to more common conditions will be explored. Gaps in the literature, unanswered questions and steps to enhance further knowledge and systematically capture experience, such as establishment of an IEM-pregnancy registry, will be summarized.

Multidisciplinary management of ornithine transcarbamylase (OTC) deficiency in pregnancy: essential to prevent hyperammonemic complications

Ornithine transcarbamylase (OTC) deficiency is the most common inborn error in the metabolism of the urea cycle with an incidence of 1 in 14,000 live births. Pregnancy can trigger potentially fatal hyperammonemic crises. We report a successful pregnancy in a 29-year-old primiparous patient with a known diagnosis of OTC deficiency since infancy. Hyperammonemic complications were avoided due to careful multidisciplinary management which included a detailed antenatal, intrapartum and postnatal plan. Management principles include avoidance of triggers, a low-protein diet and medications which promote the removal of nitrogen by alternative pathways. Triggers include metabolic stress such as febrile illness, particularly gastroenteritis, fasting and any protein loading. In our case the patient, in addition to a restricted protein intake, was prescribed sodium benzoate 4 g four times a day, sodium phenylbutyrate 2 g four times a day and arginine 500 mg four times a day to aid excretion of ammonia and reduce flux through the urea cycle.