Propionic Acidemia diagnosed in Amish adults and pregnancy outcomes: A case series

Propionic acidemia (PA) is an inborn error of metabolism (IEM) that typically presents in the newborn. The Amish of North America have an increased prevalence of PA due to a founder variant in the PCCB gene. The Amish PA phenotype is variable, and some individuals remain asymptomatic and undiagnosed until adulthood. Additionally, there are limited reports of pregnancy outcomes in Amish individuals with PA.

A retrospective single center chart review was completed on sixty Amish individuals with PA to identify individuals diagnosed as adults (18 years or older) and pregnancy outcomes. We assessed age at diagnosis, reason for PA testing, medical history prior to diagnosis including developmental delay, seizure, protein intolerance, cardiac symptoms, and anxiety. Following the diagnosis, we assessed the prevalence of prolonged QTc and dilated cardiomyopathy. We assessed our cohort for number of pregnancies, pregnancy outcomes, and peripartum complications.

Nine out of sixty individuals (15 %) were diagnosed with PA as adults. A family member with PA was the most common reason to prompt genetic testing. Cardiac symptoms were present in six of nine individuals prior to diagnosis. Three individuals diagnosed as adults had dilated cardiomyopathy and one underwent cardiac transplant. There were twenty-one pregnancies in six women with eighteen successful deliveries and three miscarriages. Two women developed peripartum cardiomyopathy. There were no acute maternal decompensations.

Our work supports the consideration that all Amish newborns be screened for PA with molecular testing to enable early diagnosis. The stark difference in peripartum outcomes requires further prospective work to ensure appropriate monitoring throughout pregnancy while respecting individual values and autonomy.