Autosomal Dominant Frontotemporal Lobar Degeneration in a Filipino Family with Progranulin Mutation

Abstract

Background: Compared to Western populations, familial frontotemporal lobar degeneration (FTLD) is rare among Asians. Progranulin (GRN) gene mutation, which is a major cause of FTLD, is likewise rare. We present a family with FTLD from the Philippines with an autosomal dominant pattern of inheritance and GRN mutation and briefly review reports of GRN mutations in Asia. Case Presentation: The proband is 66 years old with progressive nonfluent aphasia (PNFA)-corticobasal syndrome. We assessed 3 generations of her pedigree and found 11 affected relatives with heterogenous phenotypes, usually behavioral variant frontotemporal dementia (FTD) and PNFA. Neuroimaging showed atrophy and hypometabolism consistent with FTD syndromes. White matter hyperintensities were seen in affected members even in the absence of vascular risk factors. A GRN mutation R110X was found in 6 members, 3 with symptoms and 3 were asymptomatic. Plasma GRN was low (<112 ng/mL) in all mutation carriers. No mutations were found in microtubule-associated protein tau, APP, PSEN1, and PSEN2 genes, and all were APOE3. Conclusion: This is the first Filipino family with autosomal dominant FTD documented with GRN mutation. Identifying families and cohorts would contribute to therapeutic developments in an area with FTD-GRN. © 2021