Stickler syndrome is a connective tissue disorder that affects multiple systems, including the visual system. Seven genes were reported to cause Stickler syndrome in patients with different phenotypes. In this study, we aimed to evaluate the mutation features of the phenotypes of high myopia and retinal detachment. Forty-two probands diagnosed with Stickler syndrome were included. Comprehensive ocular examinations were performed. A targeted gene panel test or whole exome sequencing was used to detect the mutations, and Sanger sequencing was conducted for verification and segregation analysis. Among the 42 probands, 32 (76%) presented with high myopia and 29 (69%), with retinal detachment. Pathogenic mutations were detected in 35 (83%) probands: 27 (64%) probands had COL2A1 mutations, and eight (19%) probands had COL11A1 mutations. Truncational mutations in COL2A1 were present in 21 (78%) probands. Missense mutations in COL2A1 were present in six probands, five of which presented with retinal detachment. De novo COL2A1 mutations were detected in 10 (37%) probands, with a mean paternal childbearing age of 29.64 ± 4.97 years old. The mutation features of probands with high myopia or retinal detachment showed that the probands had a high prevalence of COL2A1 mutations, truncational mutations, and de novo mutations.

The VCAN/versican gene encodes an important component of the extracellular matrix, the chondroitin sulfate proteoglycan 2 (CSPG2/versican). Heterozygous variants targeting exon 8 of VCAN have been shown to cause Wagner disease, a rare autosomal dominant non-syndromic vitreoretinopathy that induces retinal detachment, cataracts and permanent visual loss. In this study, we report on six patients from three unrelated families with Wagner disease in whom we identified three novel copy number variations of VCAN. Quantitative real-time polymerase chain reaction analysis identified deletions, including one exon–intron boundary of exon 8 or both exons 8 and 9, causing the haploinsufficiency of VCAN mRNAs.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive syndromic form of albinism, characterized by oculocutaneous albinism (OCA) and other systemic complications. The purpose of this study was to investigate patients with HPS-associated gene mutations and describe associated ocular and extraocular phenotypes. Fifty-four probands clinically diagnosed as albinism were enrolled. Ophthalmic examinations and genetic testing were performed in all subjects. The phenotypic and genetic features were evaluated. HPS-associated gene mutation was identified in four of the patients with albinism phenotype. Clinically, photophobia, and nystagmus was detected in all (4/4) patients, and strabismus was found in one (1/4) patient. Fundus examination revealed fundus hypopigmentation and foveal hypoplasia in all (8/8) eyes. Eight novel causative mutations were detected in these four HPS probands. Five (62.5%, 5/8) of the mutations were nonsense, two of the mutations were missense (25%, 2/8), and one of the mutations was frameshift (12.5%, 1/8). All patients in our study carried compound heterozygous variants, and all these pathogenic variants were identified to be novel, with most (62.5%, 5/8) of the mutations being nonsense. Our results improved the understanding of clinical ocular features, and expanded the spectrum of known variants and the genetic background of HPS.

Objectives: Oculocutaneous albinism (OCA), a group of inherited disorders characterized by deficient melanin synthesis, leads to hypopigmentation of the skin, hair, and eyes. OCA type 2 (OCA2) is caused by mutations in OCA2. This study aimed to characterize the comprehensive clinical and genetic spectrum of OCA2, and to identify the key ocular determinants of visual acuity. Methods: We enrolled 90 probands clinically diagnosed with albinism. Whole-exome sequencing and comprehensive ophthalmic examinations were performed. Results: OCA2 was confirmed in 29 probands (32.2%). Visual impairment was distributed as mild/no impairment (30.8%), moderate (53.8%), and severe/blindness (15.4%). All patients exhibited nystagmus and photophobia. Ocular phenotype grading showed distinct distributions: iris translucency (n = 25) was 68% grade 3, 20% grade 2, 8% grade 1, and 4% grade 4; fundus hypopigmentation (n = 26) was 42.3% grade 1, 30.8% grade 2, and 26.9% grade 3; and foveal hypoplasia (n = 20) was 70% grade 4, 25% grade 3, and 5% grade 1. We identified 33 OCA2 variants (26 compound heterozygous and 3 homozygous), with missense variants accounting for 62.1% of alleles. Five variants were identified to be novel. The severity of foveal hypoplasia demonstrated a strong, statistically significant negative correlation with visual acuity (r = −0.71, p < 0.001). Conclusions: OCA2 accounts for 32.2% of albinism cases, with moderate visual impairment being the most common (53.8%). Graded phenotyping demonstrated moderate-to-severe iris translucency (88%), mild fundus hypopigmentation (42.3%), and severe (grade 4) foveal hypoplasia (70%). The severity of foveal hypoplasia emerged as an important determinant of visual acuity.

Objectives: SLC45A2-related oculocutaneous albinism type 4 (OCA4) is a genetically defined subtype of albinism; however, its ocular phenotype remains incompletely characterized. This study aimed to describe the systemic, ophthalmic, and genetic features of patients with genetically confirmed SLC45A2-related OCA4. Methods: Ninety patients with clinically diagnosed albinism were enrolled and underwent genetic testing. Patients with genetically confirmed SLC45A2-related OCA4 were included for further analysis. Demographic information, systemic pigmentation features, ophthalmic findings, and SLC45A2 variants were analyzed. Results: Five unrelated patients with genetically confirmed SLC45A2-related OCA4 were included, aged 5–33 years. Best-corrected visual acuity ranged from 0.1 to 1.0 logMAR, and spherical equivalent refractive error varied widely from −7.25 to +7.63 D. All patients exhibited iris transillumination defects and moderate-to-severe fundus hypopigmentation, both graded 2–3. Foveal hypoplasia was universally present, ranging from grade 1 to grade 4, with three patients showing grade 4 hypoplasia. Genetic analysis revealed nine disease-associated alleles representing eight distinct SLC45A2 variants: seven missense variants and one splice-altering variant. One patient carried a homozygous variant, and four carried compound heterozygous variants. Three novel variants were identified: c.1459C>G (p.Gln487Glu), c.137A>G (p.Glu46Gly), and c.561A>G. Conclusions: This study characterizes the ocular phenotype of SLC45A2-related OCA4, including iris transillumination defects, fundus hypopigmentation, and foveal hypoplasia of varying severity. Three novel SLC45A2 variants were identified, expanding the mutational spectrum of OCA4.