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Abstract Taxane‐based chemotherapy regimens are used as first‐line treatment for breast cancer. Neurotoxicity, mainly taxane‐induced peripheral neuropathy (TIPN), remains the most important dose‐limiting adverse event. Multiple genes may be associated with TIPN; however, the strength and direction of the association remain unclear. For this reason, we systematically reviewed observational studies of TIPN pharmacogenetic markers in breast cancer treatment. We conducted a systematic search of terms alluding to breast cancer, genetic markers, taxanes, and neurotoxicity in Ovid, ProQuest, PubMed, Scopus, Virtual Health, and Web of Science. We assessed the quality of evidence and bias profile. We extracted relevant variables and effect measures. Whenever possible, we performed random‐effects gene meta‐analyses and examined interstudy heterogeneity with meta‐regression models and subgroup analyses. This study follows the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) and STrengthening the REporting of Genetic Association Studies (STREGA) reporting guidance. A total of 42 studies with 19,431 participants were included. These evaluated 262 single‐nucleotide polymorphisms (SNPs) across 121 genes. We conducted meta‐analyses on 23 genes with 60 SNPs (19 studies and 6246 participants). Thirteen individual SNPs (ABCB1‐rs2032582, ABCB1‐rs3213619, BCL6/‐rs1903216, /CAND1‐rs17781082, CYP1B1‐rs1056836, CYP2C8‐rs10509681, CYP2C8‐rs11572080, EPHA5‐rs7349683, EPHA6‐rs301927, FZD3‐rs7001034, GSTP1‐rs1138272, TUBB2A‐rs9501929, and XKR4‐rs4737264) and the overall SNPs' effect in four genes (CYP3A4, EphA5, GSTP1, and SLCO1B1) were statistically significantly associated with TIPN through meta‐analysis. In conclusion, through systematic review and meta‐analysis, we found that polymorphisms, and particularly 13 SNPs, are associated with TIPN, suggesting that genetics does play a role in interindividual predisposition. Further studies could potentially use these findings to develop individual risk profiles and guide decision making.

Age-related macular degeneration (AMD) is the leading cause of central vision loss and severe blindness among the elderly population. Recently, we reported on the association of the SGCD gene (encoding for δ-sarcoglycan) polymorphisms with AMD. However, the functional consequence of Sgcd alterations in retinal degeneration is not known. Herein, we characterized changes in the retina of the Sgcd knocked-out mouse (KO, Sgcd−/−). At baseline, we analyzed the retina structure of three-month-old wild-type (WT, Sgcd+/+) and Sgcd−/− mice by hematoxylin and eosin (H&E) staining, assessed the Sgcd−protein complex (α-, β-, γ-, and ε-sarcoglycan, and sarcospan) by immunofluorescence (IF) and Western blot (WB), and performed electroretinography. Compared to the WT, Sgcd−/− mice are five times more likely to have retinal ruptures. Additionally, all the retinal layers are significantly thinner, more so in the inner plexiform layer (IPL). In addition, the number of nuclei in the KO versus the WT is ever so slightly increased. WT mice express Sgcd-protein partners in specific retinal layers, and as expected, KO mice have decreased or no protein expression, with a significant increase in the α subunit. At three months of age, there were no significant differences in the scotopic electroretinographic responses, regarding both a- and b-waves. According to our data, Sgcd−/− has a phenotype that is compatible with retinal degeneration.