Ngrn, also known as neurogranin, is a protein-coding gene. It seems to be a promising biomarker for synaptic loss. It is involved in regulating the mitochondrial 16S rRNA and intra-mitochondrial translation as part of a functional module along with WBSCR16, RPUSD3, RPUSD4, TRUB2, and FASTKD2 [1].

In a longitudinal study of patients in the Amsterdam Dementia Cohort, baseline CSF levels of NGRN in patients with Alzheimer's disease (AD) were higher than in cognitively normal participants. Baseline NGRN levels were also higher in patients with mild cognitive impairment (MCI) who progressed to AD compared with those with stable MCI, and were predictive of progression from MCI to AD. Additionally, within-person levels of NGRN increased over time in cognitively normal participants but not in patients with MCI or AD [2]. In another study comparing biomarker levels in AD, neurosyphilis (NS), and general paresis of the insane (GPI) patients, plasma NGRN levels in pooled NS populations correlated with cognitive scale scores [3].

In conclusion, Ngrn is potentially a valuable biomarker for synaptic loss, especially in relation to AD and MCI progression. Studies on Ngrn help in understanding the pathophysiology of neurodegenerative diseases, providing insights into potential diagnostic and prognostic markers related to synaptic function decline [2,3].

References:

1. Arroyo, Jason D, Jourdain, Alexis A, Calvo, Sarah E, Root, David E, Mootha, Vamsi K. 2016. A Genome-wide CRISPR Death Screen Identifies Genes Essential for Oxidative Phosphorylation. In Cell metabolism, 24, 875-885. doi:10.1016/j.cmet.2016.08.017. https://pubmed.ncbi.nlm.nih.gov/27667664/

2. Kester, Maartje I, Teunissen, Charlotte E, Crimmins, Daniel L, Holtzman, David M, Fagan, Anne M. . Neurogranin as a Cerebrospinal Fluid Biomarker for Synaptic Loss in Symptomatic Alzheimer Disease. In JAMA neurology, 72, 1275-80. doi:10.1001/jamaneurol.2015.1867. https://pubmed.ncbi.nlm.nih.gov/26366630/

3. Zhang, Min, Zhong, Xiaomei, Shi, Haishan, Dai, Chunying, Ning, Yuping. . BACE1 and Other Alzheimer's-Related Biomarkers in Cerebrospinal Fluid and Plasma Distinguish Alzheimer's Disease Patients from Cognitively-Impaired Neurosyphilis Patients. In Journal of Alzheimer's disease : JAD, 77, 313-322. doi:10.3233/JAD-200362. https://pubmed.ncbi.nlm.nih.gov/32804135/