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.

Repeatedly in Rhabdomyolysis.

ABSTRACT: Repeated presentations of a rare symptom in a patient should make a physician stop and evaluate for rare conditions. This is a report of a teenager with multiple episodes of rhabdomyolysis and weakness. He was eventually diagnosed as having McArdle muscular dystrophy, or glycogen storage disease type V. His rhabdomyolysis has been severe, with a creatinine kinase level of >320,000 U/L, myoglobinuria, transaminitis, and elevated bilirubin. He has a low threshold for triggering rhabdomyolysis, such as doing an hour of aerobic exercise 2 days in a row. McArdle disease is a glycogen storage disorder in which the skeletal muscle cannot convert glycogen to glucose. Unlike other glycogen storage disorders, McArdle muscular dystrophy only affects the skeletal muscle, sparing the brain and visceral organs, leading to a vague phenotype. These patients have exercise intolerance, muscle cramps, and rhabdomyolysis. Many patients report loading with simple carbohydrates before exercise, as they have learned that this can increase their stamina. The vague symptoms can lead to decades of delay in diagnosis and significant mismanagement. Rhabdomyolysis is the most dangerous sign of McArdle disease, and it can lead to acute kidney injury, resulting in renal failure requiring dialysis in the severest cases.Rhabdomyolysis has numerous causes, but when it is recurrent, especially with seemingly insignificant triggers, one needs to develop a broader differential and pursue advanced testing. This testing can include specific exercise tests, genetic sequencing, and muscle biopsy. This case report will guide the clinician through the process of evaluating recurrent rhabdomyolysis, working through the differential diagnosis and testing options.1.