Atypical teratoid/rhabdoid tumors (AT/RT) are malignant central nervous system (CNS) tumors. Typically, AT/RT is classified as SMARCB1 (INI-1) deficient or as SMARCA4 (BRG1) deficient. In this case, we describe a unique case of AT/RT with a novel SMARCA4 missense variant identified on next-generation sequencing but retained expression of INI-1 and BRG-1 on immunohistochemistry. Diagnosis of the tumor and discovery of the novel SMARCA4 variant was only possible after comprehensive tumor molecular testing tailored for pediatric malignancies. This case highlights the importance of molecular genetic testing as part of a workup in neoplasms concerning for possible AT/RT.
MAF encodes a transcription factor involved in T-helper-2 (Th2) cell differentiation. Heterozygous pathogenic variants in MAF have been observed in both isolated and syndromic congenital cataract cases; genotype–phenotype correlations are based on the location of the variant within the gene. Variants in the N-terminus domain of MAF are associated with cataracts as part of Aymé-Gripp syndrome. The purpose of this report is to expand the ocular phenotypic spectrum of Aymé-Gripp syndrome by describing a patient with MAF variant c.185C>G, p.Thr62Arg, and the traditional systemic findings and congenital cataracts as well as an unusual feature of pigmentary retinopathy, which has not been previously reported in Aymé-Gripp syndrome. Additionally, a comprehensive review of the literature was completed to report ocular genotype–phenotype data on previously reported patients with MAF-associated Aymé-Gripp syndrome.
Background/Objectives: While ocular albinism (OA) is usually associated with reduced vision, nystagmus, and foveal hypoplasia, there is phenotypic variability in iris and fundus hypopigmentation. Hemizygous pathogenic/likely pathogenic (P/LP) variants in GPR143 at X: 151.56–151.59 have been shown in the literature to be associated with OA. The purpose of this study was to report the case of a Hispanic male with X-linked inherited OA associated with a hemizygous GPR143 variant and to review the literature relating to genotype–phenotype associations with GPR143 and OA. Methods: After consent to an IRB-approved protocol, a 14-year-old Hispanic male patient with OA and his parents underwent whole genome sequencing (WGS) in 2023. Two maternal uncles with nystagmus underwent targeted variant testing in 2024. A literature review of reported GPR143 variants was completed. Results: A male with reduced visual acuity, infantile-onset nystagmus, foveal hypoplasia, and iris hypopigmentation was identified to have the variant GPR143, c.455+3A>G, which was also present in his mother and two affected maternal uncles. This variant has been previously identified in other Hispanic patients of Mexican descent. Additionally, 127 variants were identified in the literature and reported to be associated with OA. All patients had reduced visual acuity (average 0.71 ± 0.23 logMAR), 99% had nystagmus, 97% foveal hypoplasia, 79% fundus hypopigmentation, and 71% iris hypopigmentation. Of those patients with reported optotype best corrected visual acuity (BCVA), eight (9%) had VA from 20/25 to 20/40, 24 (24%) had VA from 20/50 to 20/80, and 63 (67%) had VA from 20/100 to 20/200. The most frequent type of variant was missense (31%, n = 39). Frameshift and nonsense variants were associated with the lowest rates of iris hypopigmentation (50% [n = 11] and 44% [n = 8], respectively; p = 0.0068). Conclusions: This case represents phenotypic variability of GPR143-associated OA and highlights the importance of repeat genetic testing and independent analyses of test results for accurate variant classification, particularly in non-White and Hispanic patients. Further studies in more diverse populations are needed to better develop genotype–phenotype associations for GPR143-associated OA.