No abstract

Mutations in granulin (GRN) have been associated with neurodegenerative diseases, such as frontotemporal lobar degeneration (FTLD) and neuronal ceroid lipofuscinosis (NCL). In Portugal, GRN mutations account for around half of all FTLD cases with known genetic origin. Here, we describe the generation and characterization of three human-induced pluripotent stem cell (hiPSC) lines from a Portuguese family harboring heterozygous and homozygous GRN mutation. hiPSCs were reprogrammed from human dermal fibroblasts by episomal nucleofection of the Yamanaka factors. The new generated lines were positive for pluripotency markers, could be further differentiated to cells expressing all trilineage markers, and presented a normal karyotype. They were also capable of differentiating into 3D brain organoids and presented a significant decrease in progranulin protein levels. Hence, these cell lines constitute suitable new tools to elucidate the pathophysiological mechanisms associated with the GRN mutations in the context of FTLD.

Disruptions in the MBD5 gene have been linked with an array of clinical features such as global developmental delay, intellectual disability, autistic-like symptoms, and seizures, through unclear mechanisms. MBD5 haploinsufficiency has been associated with the disruption of primary cilium-related processes during early cortical development, and this has been reported in many neurodevelopmental disorders. In this study, we describe the clinical history of a 12-year-old child harboring a novel MBD5 rare variant and presenting psychomotor delay and seizures. To investigate the impact of MBD5 haploinsufficiency on neural primary cilia, we established a novel patient-derived cell line and used CRISPR-Cas9 technology to create an isogenic control. The patient-derived neural progenitor cells revealed a decrease in the length of primary cilia and in the total number of ciliated cells. This study paves the way to understanding the impact of MBD5 haploinsufficiency in brain development through its potential impact on neural primary cilia.