👤 Roberta Mascia

Membranous nephropathy (MN) is a leading cause of nephrotic syndrome (NS). Since the identification of anti-phospholipase A2 receptor (anti-PLA2R) antibodies in 2009, the use of laser microdissection and tandem mass spectrometry (LMD/MS) has allowed the discovery of several target antigens in MN. In this retrospective cohort study, adult patients evaluated at the Division of Nephrology at Brotzu Hospital (Cagliari, Italy) with biopsy-proven MN and a negative serological test for anti-PLA2R antibody underwent LMD/MS, performed at the Department of Laboratory Medicine and Pathology of Mayo Clinic (Rochester, MN, USA). Twenty-four cases of biopsy-proven MN were available for antigen detection by LMD/MS studies. High total spectral counts of PLA2R were detected in 12 out of 24 (50%) cases. In addition, high spectral counts of THSD7A and NELL1 were detected in two cases each, and EXT1/EXT2 and NCAM1 in one case each. Five putative antigens have been detected: SULF1, PGLYRP, HYAL1, THBS and SEZ6L2. Our study highlights at least two interesting considerations. First, the determination of PLA2R on renal tissue in the diagnosis of PLA2R-associated MN is emphasized since 50% of our cases were falsely diagnosed with PLA2R-negative MN based on the serum anti-PLA2R antibodies determination. Second, our study shows six patients with MN likely associated with putative antigens, two of them showing new antigens never described before in literature (HYAL1 and THBS1). This high prevalence of putative antigens in our cohort is not easily explainable and paves the way for evaluating specific factors in the Sardinian population that could explain this evidence. Show less

The purpose of this review is to highlight recent genetic studies of the Amish and Mennonite (Plain) communities. For decades, the study of genetically isolated populations has improved our understanding and management of genetic diseases that affect all populations. Major themes of current genetic research of the Amish and Mennonites include new causative gene and new candidate gene discovery, phenotype expansion of previously identified genetic disease, and a target for AAV9-mediated gene therapy. Additionally, several genome-wide association studies (GWAS) examining complex traits such as dementia, cardiometabolic disease, and age-related macular degeneration have been conducted. Finally, clinically relevant studies of attitudes of the Plain community towards genetic testing and telemedicine, as well as reviews of and management suggestions for the Amish variants of propionic acidemia and APOB -associated familial hypercholesterolemia have been recently published. Recent genetic studies of the Plain community continue to highlight the value of studying isolated populations to propel genetic disease discovery and treatment. Additionally, population-specific polygenic risk scores are needed for underrepresented and minority populations, to avoid exacerbating disparities in medical genetics care. Finally, it is important for clinicians to develop management guidelines for variants common in this rapidly growing population, such as propionic acidemia. Show less