Secondary Membranous Nephropathy and Immunodeficiency due to a Novel Biallelic Variant in CARMIL2

The cytosolic capping protein, Arp2/3 and myosin-I linker protein 2 or CARMIL2 plays an important role in T/B/NK cell function. Biallelic disease causing variants in CARMIL2 are known to cause immunodeficiency 58. We report a 13-year-old girl with recurrent infections, dermatitis and nephrotic syndrome since childhood. Her renal biopsy was suggestive of membranous nephropathy. Exome sequencing showed a homozygous novel stopgain variant, c.520C>T in CARMIL2 (NM_001013838.3). We expand the phenotypic spectrum of CARMIL2 related immunodeficiency to include membranous nephropathy secondary to probable immune dysregulation.