Biology subjects

Nurnberg, P.

Publications and source records attributed to Nurnberg, P..

3 recordsLinked to original sources

bioRxiv2025

CCB79 is a primate-specific cilium initiation factor essential to maintain neural progenitor diversity in developing brain tissue.

Identifying the genes that regulate the accurate spatiotemporal diversity of neural progenitor cells (NPCs) helps to understand the mechanisms of human neocortex expansion. In primate brains, an additional intermediate progenitor layer, the outer subventricular zone (oSVZ), facilitates the expansion of the neocortex. Here, we identify an uncharacterized gene, KIAA0408, and show that its expression is enriched in intermediate progenitors. Removing KIAA0408 in human-induced pluripotent stem cell (iPSC)-derived brain organoids results in an impaired cortical organization characterized by abnormal cell fate and patterning defects, including the depletion of intermediate and ventral progenitors. Molecularly, KIAA0408 codes for a 79-kilodalton centriolar distal appendage protein (DAP) that controls cilium biogenesis (hereafter CCB79). CCB79 forms a complex with other DAP components and specifically localizes in the DAP at the onset of ciliogenesis, and its absence blocks ciliogenesis. Mechanistically, progenitors in 3D brain tissues are unable to form cilia, which induces aberrant hedgehog signaling and causes premature differentiation. Finally, human CCB79, rather than the mouse ortholog, rescues cilia defects, suggesting that CCB79 has undergone rapid evolution from rodents to primates to fine-tune ciliogenesis for proper brain development.

neuroscience↗

bioRxiv2017

Heterogeneous Contribution of Microdeletions in the Development of Common Generalized and Focal epilepsies

BackgroundMicrodeletions are known to confer risk to epilepsy, particularly at genomic rearrangement \"hotspot\" loci. However, deciphering their role outside hotspots and risk assessment by epilepsy sub-type has not been conducted.\n\nMethodsWe assessed the burden, frequency and genomic content of rare, large microdeletions found in a previously published cohort of 1,366 patients with Genetic Generalized Epilepsy (GGE) plus two sets of additional unpublished genome-wide microdeletions found in 281 Rolandic Epilepsy (RE) and 807 Adult Focal Epilepsy (AFE) patients, totaling 2,454 cases. These microdeletion sets were assessed in a combined analysis and in sub-type specific approaches against 6,746 ethnically matched controls.\n\nResultsWhen hotspots are considered, we detected an enrichment of microdeletions in the combined epilepsy analysis (adjusted-P= 2.00x10-7; OR = 1.89; 95%-CI: 1.51-2.35), where the implicated microdeletions overlapped with rarely deleted genes and those involved in neurodevelopmental processes. Sub-type specific analyses showed that hotspot deletions in the GGE subgroup contribute most of the signal (adjusted-P = 1.22x10-12; OR = 7.45; 95%-CI = 4.20-11.97). Outside hotspot loci, microdeletions were enriched in the GGE cohort for neurodevelopmental genes (adjusted-P = 4.78x10-3; OR = 2.30; 95%-CI = 1.42-3.70), whereas no additional signal was observed for RE and AFE. Still, gene content analysis was able to identify known (NRXN1, RBFOX1 and PCDH7) and novel (LOC102723362) candidate genes affected in more than one epilepsy sub-type but not in controls.\n\nConclusionsOur results show a heterogeneous effect of recurrent and non-recurrent microdeletions as part of the genetic architecture of GGE and a minor to negligible contribution in the etiology of RE and AFE.

genetics↗

bioRxiv2017

Reassessment Of Lesion-Associated Gene And Variant Pathogenicity In Focal Human Epilepsies

PurposeIncreasing availability of surgically resected brain tissue from Focal Cortical Dysplasia and low-grade epilepsy-associated tumor patients fostered large-scale genetic examination. However, assessment of germline and somatic variant pathogenicity remains difficult.\n\nMethodsHere, we critically reevaluated the pathogenicity for all neuropathology-associated variants reported to date in the PubMed and ClinVar databases, including 12 disease-related genes and 88 neuropathology-associated missense variants. We (1) assessed evolutionary gene constraint using the pLI and missense z scores, (2) applied guidelines by the American College of Medical Genetics and Genomics (ACMG), and (3) predicted pathogenicity by using PolyPhen-2, CADD, and GERP.\n\nResultsConstraint analysis classified only seven out of 12 genes to be likely disease-associated, while 35 (40%) of those 88 variants were classified as being variants of unknown significance (VUS) and 53 (60%) as being likely pathogenic (LPII). Pathogenicity prediction yielded discrimination between neuropathology-associated variants (LPII and VUS) and rare variant scores obtained from individuals present in the Genome Aggregation Database (gnomAD).\n\nConclusionWe conclude that several VUS are likely disease-associated and will be reclassified by future molecular evidence. In summary, interpretation of lesion-associated gene variants remains complex while the application of current ACMG guidelines including bioinformatic pathogenicity prediction will help improving interpretation and prediction.

genetics↗