Antepartum 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.

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.

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.

Adult Presentation of Ornithine Transcarbamylase Deficiency: 2 Illustrative Cases of Phenotypic Variability and Literature Review

Ornithine transcarbamylase (OTC) deficiency is an X-linked recessive disorder that usually presents in the neonatal period. Late-onset presentation of OTC can cause mild to severe symptoms. We describe laboratory and clinical findings of late-onset presentations of OTC deficiency. We conducted a literature search using search terms "ornithine transcarbamylase deficiency," "late onset presentation," and "hyperammonemia" from January 1, 1987, to December 31, 2016, was performed. Only papers published in English were included. We searched on PubMed, MEDLINE, and Google Scholar. We also present 2 OTC deficiency cases. A total of 30 adult cases had late-onset presentation of OTC deficiency reported. The majority were women (57%) with a median age of 37 years. The median level of ammonia was 308 mmol/L and the mortality rate was 30%. Our case 1 was a 40-year-old woman who succumbed to neurologic complications after a hyperammonemia crisis following an increased protein intake. Our case 2 was a 43-year-old woman with seizures associated with increased ammonia levels. Our 2 case reports show the wide phenotypic variability and severity in late-onset presentation of OTC ranging from seizures to cerebral herniation. Our literature review is the first to detail published laboratory and neurologic sequelae of late-onset OTC deficiency.

Peak hyperammonemia and atypical acute liver failure: The eruption of an urea cycle disorder during hyperemesis gravidarum

Inborn urea cycle disorders are under-recognised metabolic causes of hyperammonemia in adults. A 28-year-old primigravida, seven weeks pregnant, affected by hyperemesis gravidarum developed acute liver injury (ALI) and then acute liver failure (ALF) in less than 48 h. Because the patient developed atypical features, especially mildly elevated aminotransferases contrasting with very high blood ammonia levels (281 μmol/L), concomitant with normal serum creatinine, an inborn error of metabolism was suspected. We performed emergency metabolic analyses, stopped all protein intake and started with intravenous (i.v.) high caloric intake, nitrogen scavenger drugs and haemodialysis. The neurological and hepatic status of the patient quickly improved together with normalisation of her ammonemia levels. High plasma glutamine and urinary orotic acid, alongside low plasma arginine, citrulline and ornithine were suggestive of an ornithine transcarbamylase deficiency, later confirmed by molecular analyses. Foetal sex was female, as determined by foetal DNA analysis in maternal blood, and foetal development was unremarkable throughout the pregnancy. Delivery was induced at 39 weeks with a close monitoring of ammonemia levels and i.v. perfusion of carbohydrates and lipids during labour and immediately post-partum to avoid hypercatabolism. Delivery was uneventful and the patient delivered a healthy female baby. Urea cycle disorders should be contemplated in non-jaundiced patients with ALI or ALF, severe hyperammonemia and normal serum creatinine regardless of serum aminotransferase levels. The prompt recognition of this rare condition and the rapid initiation of adequate metabolic therapy are mandatory to prevent irreversible neurological sequelae and to avoid liver transplantation.