Risk of Optic Pathway Glioma in Neurofibromatosis Type 1: No Evidence of Genotype–Phenotype Correlations in A Large Independent Cohort

• Main Authors: Giulia Melloni, Marica Eoli, Claudia Cesaretti, Donatella Bianchessi, Maria Cristina Ibba, Silvia Esposito, Giulietta Scuvera, Guido Morcaldi, Roberto Micheli, Elena Piozzi, Sabrina Avignone, Luisa Chiapparini, Chiara Pantaleoni, Federica Natacci, Gaetano Finocchiaro, and Veronica Saletti
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Cancers
• Subjects: key words: neurofibromatosis type 1; nf1 gene; optic pathway glioma; genotype–phenotype correlations
• Online Access: https://www.mdpi.com/2072-6694/11/12/1838

The occurrence of optic pathway gliomas (OPGs) in children with neurofibromatosis type 1 (NF1) still raises many questions regarding screening and surveillance because of the lack of robust prognostic factors. Recent studies of an overall cohort of 381 patients have suggested that the genotype may be the main determinant of the development of OPG, with the risk being higher in patients harbouring <i>NF1 </i>mutations in the 5&#8217; tertile and the cysteine/serine-rich domain. In an attempt to confirm this hypothesis, we used strict criteria to select a large independent cohort of 309 NF1 patients with defined constitutional NF1 mutations and appropriate brain images (255 directly enrolled and 54 as a result of a literature search). One hundred and thirty-two patients had OPG and 177 did not. The association of the position (tertiles and functional domains) and type of <i>NF1</i> mutation with the development of OPG was analysed using the &#967;2 test and Fisher&#8217;s exact probability test; odds ratios (ORs) with 95% confidence intervals were calculated, and Bonferroni&#8217;s correction for multiple comparisons was applied; multiple logistic regression was also used to study genotype&#8722;phenotype associations further. Our findings show no significant correlation between the site/type of NF1 mutation and the risk of OPG, and thus do not support the hypothesis that certain constitutional mutations provide prognostic information in this regard. In addition, we combined our cohort with a previously described cohort of 381 patients for a total of 690 patients and statistically re-analysed the results. The re-analysis confirmed that there were no correlations between the site (tertile and domain) and the risk of OPG, thus further strengthening our conclusions.