Alexander Ing

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.

Heterozygous de novo and inherited biallelic pathogenic variants in DNM1 have been reported in association with autosomal dominant (AD) and autosomal recessive (AR) developmental and epileptic encephalopathy, respectively, due to aberrant dynamin function or expression, with each inheritance pattern associated with a different mechanism of disease. We report an instance of DNM1 ‐related early infantile developmental and epileptic encephalopathy due to compound heterozygous pathogenic variants with different functional effects: the de novo dominant negative‐associated c.194C>A (p.Thr65Asn), and the maternally inherited loss of function‐associated c.850C>T (p.Gln284*). We describe this patient's severe clinical presentation and disease progression as compared to those previously reported with either AD or AR DNM1 ‐related disease. We hypothesize about the interactions and outcomes of the two variants at the molecular level following review of in vitro and in vivo functional data and demonstrate the utility of long‐read genome sequencing for phasing the variants and confirming this individual's molecular diagnosis.

Inherited retinal diseases (IRDs) are clinically and genetically diverse conditions whose heterogeneity makes molecular diagnosis challenging. These challenges can lead to interpretation discordance which has a particular impact on gene-targeted therapies for IRD. Discordance was evaluated in a clinical testing cohort and in ClinVar. 140 sequence variants identified through genetic testing in a cohort of pediatric participations with IRD were reclassified using the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP) guidelines for variant interpretation. ClinVar datasets from December 2, 2019 and January 3, 2022 for the gene RPE65 were analyzed for discordance. The discordance rate in the pediatric cohort was 22.2%. Discordance in ClinVar increased from 23.6% to 36.6%. Discordance in the pediatric cohort may have been impacted by subjective application of the ACMG/AMP guidelines and heterogeneity in IRD. Subjectivity in the guidelines, laboratory differences, and lack of interpretation review may have contributed to discordance in ClinVar. Work to improve interpretation for IRD should include better understanding of the genetic influences of IRD and optimization of the ACMG/AMP guidelines for this field.

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.

The recurrent chromosome 16p11.2 BP4‐BP5 microdeletion (MIM #611913) predisposes to a neurodevelopmental disorder with variable associated congenital anomalies and susceptibility to early‐onset obesity. We identified 22 new individuals with proximal 16p11.2 deletions through retrospective data analysis at our institution and performed phenotyping through in‐depth chart review. Our cohort exhibited a spectrum of neurodevelopmental abnormalities largely consistent with other publications, however they also were found to have a higher rate than expected of congenital anomalies, some of which have not yet been reported in association with 16p11.2 microdeletions to our knowledge. This series contributes to the body of data on this population, which we anticipate will continue to evolve along with increased uptake of genetic testing.

The MAF gene encodes a transcription factor in which pathogenic variants have been associated with both isolated and syndromic congenital cataracts. We aim to review the MAF variants in the C-terminal DNA-binding domain associated with non-syndromic congenital cataracts and describe a patient with a novel, disease-causing de novo missense variant. Published reports of C-terminal MAF variants and their associated congenital cataracts and ophthalmic findings were reviewed. The patient we present and his biological parents had genetic testing via a targeted gene panel followed by trio-based whole exome sequencing. A 4-year-old patient with a history of bilateral nuclear and cortical cataracts was found to have a novel, likely pathogenic de novo variant in MAF, NM_005360.5:c.922A>G (p.Lys308Glu). No syndromic findings or anterior segment abnormalities were identified. We report the novel missense variant, c.922A>G (p.Lys308Glu), in the C-terminal DNA-binding domain of MAF classified as likely pathogenic and associated with non-syndromic bilateral congenital cataracts.

CHARGE syndrome is a rare multi‐system condition associated with CHD7 variants. However, ocular manifestations and particularly ophthalmic genotype–phenotype associations, are not well‐studied. This study evaluated ocular manifestations and genotype–phenotype associations in pediatric patients with CHARGE syndrome. A retrospective chart review included pediatric patients under 20 years‐old with clinical diagnosis of CHARGE syndrome and documented ophthalmic examination. Demographics, genetic testing, and ocular findings were collected. Comprehensive literature review enhanced the genotype–phenotype analysis. Forty‐two patients (20 male) underwent eye examination at an average age of 9.45 ± 6.52 years‐old. Thirty‐nine (93%) had ophthalmic manifestations in at least one eye. Optic nerve/chorioretinal colobomas were most common (38 patients), followed by microphthalmia (13), cataract (6), and iris colobomas (4). Extraocular findings included strabismus (32 patients), nasolacrimal duct obstructions (11, 5 with punctal agenesis), and cranial nerve VII palsy (10). Genotype–phenotype analyses (27 patients) showed variability in ocular phenotypes without association to location or variant types. Splicing (10 patients) and frameshift (10) variants were most prevalent. Patients with CHARGE syndrome may present with a myriad of ophthalmic manifestations. There is limited data regarding genotype–phenotype correlations and additional studies are needed.

Nonketotic hyperglycinemia (NKH) is a relatively well‐characterized inborn error of metabolism that results in a combination of lethargy, hypotonia, seizures, developmental arrest, and, in severe cases, death early in life. Three genes encoding components of the glycine cleavage enzyme system— GLDC, AMT, and GCSH —are independently associated with NKH. We report on a patient with severe NKH in whom the homozygous pathogenic variant in AMT (NM_000481.3):c.602_603del (p.Lys201Thrfs*75) and the homozygous likely pathogenic variant in GLDC (NM_000170.2):c.2852C>A (p.Ser951Tyr) were both identified. Our patient demonstrates a novel combination of two homozygous disease‐causing variants impacting the glycine cleavage pathway at two different components, and elicits management‐ and genetic counseling‐related challenges for the family.

Pathogenic heterozygous variants in DHX16 have been recently identified in association with a variety of clinical features, including neuromuscular disease, sensorineural hearing loss, ocular anomalies, and other phenotypes. All DHX16 disease‐causing variants previously reported in affected individuals are missense in nature, nearly all of which were found to be de novo. Here we report on a patient with neuromuscular disease, hearing loss, retinal degeneration, and previously unreported phenotypic features including mitochondrial deficiency and primary ovarian insufficiency, in whom a novel de novo likely pathogenic variant in DHX16 NM_003587.4:c.2033A > G (p.Glu678Gly) was identified. Furthermore, we conducted an in‐depth literature review of DHX16's role in disease and utilized high‐performing in silico prediction algorithms to compare and contrast the predicted effects of all reported disease‐associated DHX16 variants on protein structure and function.