Inverted internal limiting membrane flap combined with subretinal viscoelastic injection for large or chronic macular holes.

Purpose: To report two cases with a large or chronic macular hole (MH) that was closed by combining the inverted internal limiting membrane (ILM) flap technique with the injection of ophthalmic viscoelastic device (OVD) into the subretinal space through the MH. Observations: A 76-year-old woman was referred to our clinic for surgery of a MH with a maximum diameter of 1089 µm as determined by optical coherence tomography (OCT). Her visual acuity was 20/50 in the left eye after vitrectomy was performed at a local clinic to remove vitreous opacities. For our surgery, the ILM was peeled and the ILM flap was inverted and placed over the MH. Then, cohesive OVD was injected into the subretinal space through the MH to create a retinal detachment around the MH. The MH was closed by a gas tamponade, and the vision improved to 20/40. The second patient was a 62-year-old man whose vision had been decreasing for 3 years, and he was referred to our clinic. His vision was 20/40 in the left eye and OCT detected a MH with a maximum diameter of 853 µm. After core vitrectomy, the ILM was peeled, inverted, and placed over the MH. Then, dispersive and cohesive OVD was injected through the MH. During this procedure, the MH appeared to enlarge and elevate. Then a yellowish arch-shaped lesion appeared at the temporal edge of the macular detachment. The intraoperative OCT showed that the curled-up retinal pigment epithelium (RPE) within the temporal arch-shaped lesion was adherent to the outer retinal layer. Following gas tamponade, the MH was closed but the patient noticed a paracentric scotoma on the nasal side. The fundus autofluorescence (FAF) images showed a hypo-autofluorescent lesion corresponding to the RPE defect. At postoperative 4 months, his visual acuity had improved to 20/22 and the OCT image showed that the MH was closed with a recovery of the ellipsoid zone of the photoreceptors. The subjective paracentric scotoma disappeared, however the hypo-autofluorescent lesion persisted. Conclusions and importance: A combination of the inverted ILM flap and the subretinal injection of OVD can close a large or chronic MH. An RPE detachment caused by injecting OVD into the subretinal space should be avoided.

Retinal hemorrhages and damages from tractional forces associated with infantile abusive head trauma evaluated by wide-field fundus photography.

We evaluated the distribution and types of retinal hemorrhages (RHs) and other damages in eyes with abusive head trauma (AHT). This retrospective, consecutive case series of AHT and non-AHT conditions involved 54 children with AHT, 43 children with head bruises, and 49 children with blunt eye trauma, each of non-AHT supported by reliable witness accounts. RHs and other damage were evaluated using ophthalmoscopy and wide-field fundus photography. A variety of RH types and other damage were identified in the AHT group but not in the non-AHT group. RHs in AHT extended from the posterior pole to the far periphery in 77% of eyes and on/near the veins in 86% and arteries in 85%, most of which were in the far periphery. Retinoschisis, white-dot lesions, and retinal folds were seen even in the far periphery. RHs on/near the veins and arteries, retinoschisis, and retinal folds suggest a traumatic mechanism of the tractional force of the vitreous that is attached to the entire retinal surface. Identifying the distribution and arterio and venous origins of RHs is a key factor in determining the association with trauma. Thus, wide-field fundus photography is useful to record and evaluate the origin of the RHs and other retinal damage.

Establishment and visual analysis of CBA/J-Pde6bY347Y/Y347X and C3H/HeJ-Pde6bY347Y/Y347X mice.

In CBA/J and C3H/HeJ mice, retinitis pigmentosa is inherited as an autosomal-recessive trait due to a mutation in Pde6b, which encodes cGMP phosphodiesterase subunit b. In these strains, the Y347X mutation in Pde6b leads to the upregulation of cGMP levels, increased Ca2+ influx induces rod death, and the outer segment and rod cells entirely disappeared by 35 days after birth. In the present study, we utilized the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) 9-mediated gene editing to repair the Y347X mutation in CBA/J and C3H/HeJ mice. Evaluation of the established CBA/J-Pde6bY347Y/Y347X and C3H/HeJ-Pde6bY347Y/Y347X mice, which were confirmed to have normal retinal layers by live fundoscopic imaging and histopathological analysis, revealed improved visual acuity based on the visual cliff and light/dark latency tests. Furthermore, our analyses revealed that the visible platform test was a more effective tool for testing visual behavior in these mice. The results suggest that the established strains can serve as control groups for CBA/J and C3H/HeJ in ophthalmology studies involving retinitis pigmentosa.

Modeling of Retina and Optic Nerve Ischemia-Reperfusion Injury through Hypoxia-Reoxygenation in Human Induced Pluripotent Stem Cell-Derived Retinal Ganglion Cells.

Retinal ganglion cells (RGCs) are specialized projection neurons that constitute part of the retina, and the death of RGCs causes various eye diseases, but the mechanism of RGC death is still unclear. Here, we induced cell death in human induced pluripotent stem cell (hiPSC)-derived RGC-rich retinal tissues using hypoxia-reoxygenation in vitro. Flow cytometry, immunochemistry, and Western blotting showed the apoptosis and necrosis of RGCs under hypoxia-reoxygenation, and they were rescued by an apoptosis inhibitor but not by a necrosis inhibitor. This revealed that the cell death induced in our model was mainly due to apoptosis. To our knowledge, this is the first model to reproduce ischemia-reperfusion in hiPSC-derived RGCs. Thus, the efficacy of apoptosis inhibitors and neuroprotective agents can be evaluated using this model, bringing us closer to clinical applications.

A pediatric case of congenital stromal corneal dystrophy caused by the novel variant c.953del of the DCN gene.

We report a 1-year-old girl with congenital stromal corneal dystrophy confirmed by genetic analysis. The ocular phenotype included diffuse opacity over the corneal stroma bilaterally. We performed a genetic analysis to provide counseling to the parents regarding the recurrence rate. Whole exome sequencing was performed on her and her parents, and a novel de novo variant, NM_001920.5: c.953del, p.(Asn318Thrfs*10), in the DCN gene was identified in the patient.

Integrator complex subunit 15 controls mRNA splicing and is critical for eye development.

The eye and brain are composed of elaborately organized tissues, development of which is supported by spatiotemporally precise expression of a number of transcription factors and developmental regulators. Here we report the molecular and genetic characterization of Integrator complex subunit 15 (INTS15). INTS15 was identified in search for the causative gene(s) for an autosomal-dominant eye disease with variable individual manifestation found in a large pedigree. While homozygous Ints15 knockout mice are embryonic lethal, mutant mice lacking a small C-terminal region of Ints15 show ocular malformations similar to the human patients. INTS15 is highly expressed in the eye and brain during embryogenesis and stably interacts with the Integrator complex to support small nuclear RNA 3' end processing. Its knockdown resulted in missplicing of a large number of genes, probably as a secondary consequence, and substantially affected genes associated with eye and brain development. Moreover, studies using human iPS cells-derived neural progenitor cells showed that INTS15 is critical for axonal outgrowth in retinal ganglion cells. This study suggests a new link between general transcription machinery and a highly specific hereditary disease.

Biallelic CDK9 variants as a cause of a new multiple-malformation syndrome with retinal dystrophy mimicking the CHARGE syndrome.

CDK9 has been considered a candidate gene involved in the CHARGE-like syndrome in a pair of cousins. We report an 8-year-old boy with a strikingly similar phenotype including facial asymmetry, microtia with preauricular tags and bilateral hearing loss, cleft lip and palate, cardiac dysrhythmia, and undescended testes. Joint contracture, no finger flexion creases, and large halluces were the same as those of a previously reported patient with homozygous CDK9 variants. The ocular phenotype included blepharophimosis, lacrimal duct obstruction, eyelid dermoids, Duane syndrome-like abduction deficit, and congenital cataracts. Optical coherence tomography and electroretinography evaluations revealed severe retinal dystrophy had developed at an early age. Trio-based whole-exome sequencing identified compound heterozygous variants in CDK9 [p.(A288T) of maternal origin and p.(R303C) of paternal origin] in the patient. Variants' kinase activities were reduced compared with wild type. We concluded that CDK9 biallelic variants cause a CHARGE-like malformation syndrome with retinal dystrophy as a distinguishing feature.

SEVERE RECURRENT FIBROVASCULAR PROLIFERATION AFTER COMBINED INTRAVITREAL BEVACIZUMAB INJECTION AND LASER PHOTOCOAGULATION FOR AGGRESSIVE POSTERIOR RETINOPATHY OF PREMATURITY.

PURPOSE: To describe the clinical features of severe recurrent fibrovascular proliferation after intravitreal bevacizumab injections and laser photocoagulation for aggressive posterior retinopathy of prematurity. METHODS: This retrospective, nonrandomized case series reviewed the medical and ophthalmic records in the referral hospital and our hospital. PATIENTS: Four patients (seven eyes) with aggressive posterior retinopathy of prematurity. RESULTS: The patients were referred for vitrectomy with/without lensectomy for recurrent fibrovascular proliferation with a tractional retinal detachment after combined intravitreal bevacizumab injections and laser photocoagulation. Three patients were born at 22 weeks or 23 weeks' gestational age and one patient at 29 weeks' gestational age. Preoperatively, fluorescein angiography images showed all eyes had tractional retinal detachment from regrowth of fibrovascular proliferation 3 months to 5 months after the intravitreal bevacizumab injection and abnormal retinal vasculature; four eyes had a broad ischemic retina. Postoperatively, four eyes had retinal attachment and three eyes a total retinal detachment. Neovascular glaucoma developed in five of the seven eyes during the clinical course. CONCLUSION: Severe fibrovascular proliferation may recur due to widespread retinal ischemia with capillary dropout and abnormal vasculature after failed combined intravitreal bevacizumab and laser photocoagulation therapy as the initial treatment for aggressive posterior retinopathy of prematurity. Careful follow-up is important especially after anti-vascular endothelial growth factor treatment, with recognition that severe reactivation is possible.

Structure of the Retinal Margin and Presumed Mechanism of Retinal Detachment in Choroidal Coloboma.

PURPOSE: To describe the vitreoretinal structure at the margin of the choroidal coloboma in infants and older patients using swept-source (SS) OCT. DESIGN: Retrospective case series. PARTICIPANTS: Nineteen eyes of 16 patients with choroidal coloboma (7 males, 9 females; average age, 12.3 ± 7.1 years). METHODS: The patients were classified into 2 groups: infants 1 year of age or younger (3 eyes) and older patients (16 eyes). Each finding on SS OCT was documented according to previously defined histopathologic findings. MAIN OUTCOME MEASURES: Description of the SS OCT features of choroidal colobomas. RESULTS: Swept-source OCT showed that the extracolobomatous retina centrally traversed the margin to continue as the marginal intercalary membrane (MICM), whereas the outer layers of the MICM were reversed at the point (point of reversal [POR]). The expected duplication was seen in all infant eyes, but in none of the older eyes whose outer layers of the MICM were ambiguous. However, at the boundary between the layered MICM and monolayered central intercalary membrane (CICM), the POR was detectable in all patients. Further SS OCT analysis showed that the MICM schisis and CICM schisis occurred simultaneously with vitreous traction. Retinal detachments (RDs) seen in 4 eyes were connected to the only MICM schisis, and a MICM break was identified in 1 eye. Swept-source OCT showed that retinal pigment epithelial hyperplasia adhered tightly to the retina and that the glial triangle was adhered tightly to the sclera, indicating barriers to the development of RD after MICM schisis. CONCLUSIONS: Swept-source OCT first visualized the POR in infant eyes and showed that the POR was identifiable despite the atrophic changes in the outer layer of the MICM in the older eyes. Based on the POR location, we confirmed that the intercalary membranes reported in previous OCT studies were clearly differentiated between the MICM and CICM. We also showed that the presence of MICM and CICM schisis resulted from vitreous traction at the coloboma margin and that MICM breaks induced RD only if the barrier that prevented the development of RD was broken.

Early laser photocoagulation for extensive retinal avascularity in infants with incontinentia pigmenti.

PURPOSE: To describe the clinical features and treatment outcomes of severe retinopathy in eyes with incontinentia pigmenti (IP) of infants within a few months of birth. STUDY DESIGN: Retrospective clinical study. METHODS: Six eyes of three patients (6-day-old girl, 5-month-old girl, and 14-day-old boy) with IP were examined and treated under general anesthesia. Ophthalmologic examinations were performed including images from wide-angle fluorescein angiography (FA), swept-source optical coherence tomography (OCT), and OCT angiography (OCTA). RESULTS: Ophthalmoscopy showed prominent vascular tortuosity in five eyes, retinal hemorrhages in four eyes, and incomplete vascular development in two eyes. FA showed extensive avascularity including the posterior pole of the retina in all cases except one eye. Prompt and intensive laser photocoagulation stabilized the pre-proliferative severe retinopathy in five eyes; however, foveal structure and vessel anomalies were detected in three of six eyes by OCT and two of five eyes by OCTA. CONCLUSION: Severe retinopathy in the neonatal period and infancy was present not only in the periphery but also in the posterior pole including the fovea, which might be related to retinal vascular maldevelopment. It is, therefore, recommended that wide-angle fundus FA examination be performed in the early postnatal period to detect early signs of severe retinopathy in infants with IP.

Retinal structure in Leber's congenital amaurosis caused by RPGRIP1 mutations.

This study aimed to evaluate retinal structure in the early stage of Leber's congenital amaurosis (LCA) caused by RPGRIP1 mutations. Four patients from two families were included. Case 1 was a 13-year-old girl, cases 2 and 3 were 7-year-old monozygotic twin brothers of case 1, and case 4 was a 17-year-old boy. Comprehensive ophthalmic examinations were performed, including visual acuity measurements, perimetry, electroretinography (ERG), and optical coherence tomography (OCT). To identify potential pathogenic mutations, 74 genes known to cause retinitis pigmentosa or LCA were assessed using targeted next-generation sequencing. OCT showed photoreceptor outer nuclear layer (ONL) thinning in all patients. The lamellar structure was retained in all patients, whereas the ellipsoid zone was extinguished in cases 1, 2, and 3. In case 4, the ellipsoid zone was maintained at 9 years of age but became blurred at 17 years of age. In case 1, OCT indicated slight photoreceptor ONL thinning during the period between 7 and 11 years of age. Mutation analysis revealed RPGRIP1 mutations as the cause for autosomal recessive LCA in all patients. Photoreceptor ONL on OCT is relatively well preserved in the early stage of LCA caused by RPGRIP1 mutations.

Optical coherence tomography and video recording of a case of bilateral contractile peripapillary staphyloma.

PURPOSE: To report a case of bilateral contractile peripapillary staphyloma (CPS) examined by optical coherence tomography (OCT) and video recording. OBSERVATION: We report the clinical history of a male infant with bilateral CPS. Two ophthalmic examinations under general anesthesia were performed during follow-up examinations. During the first fundus examination when the infant was 4 months old, we observed staphylomatous excavation around the optic disc, an almost normal disc appearance at the bottom of the excavation, and irregular contraction bilaterally. OCT images showed deep excavation around the optic disc bilaterally and hyperreflective tissue beneath the sclera in the right eye. During the second examination when the child was 4 years and 1 month, in addition to the previous fundus findings, the fundus examination showed white fibrous tissue on the optic disc and pigmentation around the optic disc in the right eye and a retinal cyst in the left eye. Bilateral simultaneous video recordings showed that the contractions were not synchronized between the eyes. CONCLUSIONS: In a patient with bilateral CPS, we observed unsynchronized contraction between the eyes and the presence of sequential hyperreflective tissue under the sclera using bilateral ophthalmic approaches.

Molecular Diagnosis of 34 Japanese Families with Leber Congenital Amaurosis Using Targeted Next Generation Sequencing.

Leber congenital amaurosis (LCA) is a genetically and clinically heterogeneous disease, and represents the most severe form of inherited retinal dystrophy (IRD). The present study reports the mutation spectra and frequency of known LCA and IRD-associated genes in 34 Japanese families with LCA (including three families that were previously reported). A total of 74 LCA- and IRD-associated genes were analysed via targeted-next generation sequencing (TS), while recently discovered LCA-associated genes, as well as known variants not able to be screened using this approach, were evaluated via additional Sanger sequencing, long-range polymerase chain reaction, and/or copy number variation analyses. The results of these analyses revealed 30 potential pathogenic variants in 12 (nine LCA-associated and three other IRD-associated) genes among 19 of the 34 analysed families. The most frequently mutated genes were CRB1, NMNAT1, and RPGRIP1. The results also showed the mutation spectra and frequencies identified in the analysed Japanese population to be distinctly different from those previously identified for other ethnic backgrounds. Finally, the present study, which is the first to conduct a NGS-based molecular diagnosis of a large Japanese LCA cohort, achieved a detection rate of approximately 56%, indicating that TS is a valuable method for molecular diagnosis of LCA cases in the Japanese population.

Characteristics of Retinal Breaks and Surgical Outcomes in Rhegmatogenous Retinal Detachment in Familial Exudative Vitreoretinopathy.

PURPOSE: To determine the characteristics of retinal breaks and surgical outcomes in eyes with a rhegmatogenous retinal detachment (RRD) with familial exudative vitreoretinopathy (FEVR). DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Thirty-seven patients (46 eyes) with a RRD in FEVR. METHODS: The medical records were reviewed and the types, directions, and positions of the retinal breaks and surgical outcomes were analyzed. MAIN OUTCOME MEASURES: Fundus examinations, including ophthalmoscopy, fluorescein angiography, and RetCam imaging (Natus Medical Incorporated, Pleasanton, CA). RESULTS: The retinal breaks were identified as tears in 12 eyes, atrophic holes in 24 eyes, tears and atrophic holes in 2 eyes, dialysis-related in 1 eye, a retinal break in the ora serrata in 1 eye, and unidentified in 6 eyes. Most retinal breaks (86.1%) were identified only in the temporal retina. Most tears (85.7%) were observed on the demarcation line, whereas atrophic holes were identified both on the demarcation line (53.8%) and the avascular retina (42.3%). The representative tears were almond-shaped, which differs from the typical horseshoe-shaped tears. Scleral buckling was performed as the initial surgery in 37 eyes and resulted in reattachment in 35 eyes (94.6%). Vitrectomy with or without scleral buckle was performed for eyes with more complex RRD in FEVR and resulted in reattachment in 5 of 9 eyes (55.6%). In total, reattachment was achieved in 40 of 46 eyes (87.0%). There was a history of stage 1A or 2A FEVR in 45 eyes and a history of stage 2B FEVR in 1 eye. CONCLUSIONS: Our data clarified the types, directions, and positions of the retinal breaks and the effectiveness of scleral buckling as the first surgical choice for treating RRDs in FEVR.

ATYPICAL FORM OF RETINOPATHY OF PREMATURITY WITH SEVERE FIBROVASCULAR PROLIFERATION IN THE OPTIC DISK REGION.

PURPOSE: To describe severe fibrovascular proliferation that developed in the optic disk region in an atypical form of retinopathy of prematurity (ROP). METHODS: Retrospective observational case reports. RESULTS: Four patients (8 eyes) with ROP were included. Three patients were born very prematurely (24-25 weeks of gestational age; weight, 500-1,000 grams); 1 patient was born at 33 weeks of gestational age. Among all eight eyes of four patients who received prompt ROP screening and underwent laser photocoagulation, six eyes had atypical and severe fibrovascular proliferation mainly in the optic disk region; the other two eyes, including one eye with classic ROP and one eye with aggressive posterior ROP, did not have the atypical form. All eight eyes had a total to partial retinal detachment. Among the six eyes with the atypical form, early vitreous surgery with lensectomy was possible in three eyes; only late vitreous surgery with lensectomy was possible in two eyes; one eye was inoperable. Three eyes had a partial or complete reattachment, whereas three eyes had a total retinal detachment. Among the six eyes with atypical fibrovascular proliferation, only two eyes obtained light perception vision. CONCLUSION: An atypical and severe form of ROP, in which fibrovascular proliferation grew mainly from the optic disk region, needs further investigation for treatment in addition to laser photocoagulation and vitreous surgery.

Surgical treatments for fibrous tissue extending to the posterior retina in eyes with familial exudative vitreoretinopathy.

PURPOSE: To describe the clinical features and surgical outcomes of macular dragging or tractional retinal detachment that occurred as a result of fibrovascular tissue (FT) progression toward the posterior retina in eyes with familial exudative vitreoretinopathy (FEVR). METHODS: The medical records of 4 patients (2 girls, 2 boys) with FEVR were reviewed retrospectively. RESULTS: All 4 patients had retinal dragging or radial retinal folds with FT in the peripheral retina in at least 1 eye at the initial visit. During the follow-up period, all the patients had FT that progressed toward the posterior pole and developed from the peripheral FT, resulting in macular dragging or posterior tractional retinal detachment. Vitrectomy with or without scleral buckling and laser photocoagulation were performed in all 4 cases, with removal of the FT in the posterior pole and segmentation of the FT between the posterior and peripheral FT. The traction resolved postoperatively and the retina extended in all 4 cases. CONCLUSIONS: In 4 cases with FEVR, the FT developed from the peripheral FT, progressed toward the posterior retina, and generated traction. Vitrectomy with focal removal and segmentation of the FT in the posterior pole might be a good surgical option in such eyes.

Atypical intravitreal growth of retinoblastoma with a multi-branching configuration.

PURPOSE: To report the clinical and histopathological findings of atypical intravitreal growth of a retinoblastoma with a multi-branching configuration. OBSERVATIONS: A 7-month-old boy was referred to our hospital due to leukocoria in the right eye. Ophthalmic examinations identified multi-branching vessels surrounded by diaphanous tissue behind the lens in the right eye. Imaging modalities showed microphthalmos, band-shaped calcification, and cystic lesions in that eye. Because it was difficult to rule out congenital anomalies such as persistent fetal vasculature due to the atypical clinical features of retinoblastoma, we performed a biopsy using a limbal approach. An intraoperative rapid pathological examination led to the definitive diagnosis of retinoblastoma. The right eye was enucleated and postoperative adjuvant chemotherapy was administered. Immunohistochemical staining of the enucleated eyeball showed that the tumoral cells and diaphanous tumoral tissue around the vessels were positive for neuron-specific enolase and Ki-67 and partially positive for glial fibrillary acidic protein (GFAP). The vessels of the diaphanous tissues near the tumoral mass were stained by GFAP and those behind the lens were stained faintly. CONCLUSIONS AND IMPORTANCE: We described an atypical retinoblastoma of pseudo-persistent fetal vasculature with a multi-branching configuration, which expanded the clinical spectrum of retinoblastoma. Such a specific growth pattern of the embryonic tumor might occur with a combination of retinal development, retinal vasculature, and hyaloid vascular system.

Effects of neuroactive agents on axonal growth and pathfinding of retinal ganglion cells generated from human stem cells.

We recently established a novel method for generating functional human retinal ganglion cells (RGCs) from human induced pluripotent cells (hiPSCs). Here, we confirmed that RGCs can also be generated from human embryonic stem cells (hESCs). We investigated the usefulness of human RGCs with long axons for assessing the effects of chemical agents, such as the neurotrophic factor, nerve growth factor (NGF), and the chemorepellent factors, semaphorin 3 A (SEMA3A) and SLIT1. The effects of direct and local administration of each agent on axonal projection were evaluated by immunohistochemistry, real-time polymerase chain reaction (PCR), and real-time imaging, in which the filopodia of the growth cone served as an excellent marker. A locally sustained agent system showed that the axons elongate towards NGF, but were repelled by SEMA3A and SLIT1. Focally transplanted beads that released SLIT1 bent the pathfinding of axons, imitating normal retinal development. Our innovative system for assessing the effects of chemical compounds using human RGCs may facilitate development of novel drugs for the examination, prophylaxis, and treatment of diseases. It may also be useful for observing the physiology of the optic nerve in vitro, which might lead to significant progress in the science of human RGCs.

SOX2 nonsense mutation in a patient clinically diagnosed with non-syndromic hypogonadotropic hypogonadism.

Hypogonadotropic hypogonadism (HH) is a genetically heterogeneous condition that occurs either as an isolated disorder or as a component of congenital malformation syndromes. SOX2 is a causative gene of syndromic HH characterized by anophthalmia, microphthalmia, or coloboma and other neurological defects such as epilepsy. To date, the causal relationship between SOX2 abnormalities and non-syndromic HH remains speculative. Here, we identified a nonsense mutation of SOX2 in a male patient clinically diagnosed with non-syndromic HH. The patient had epilepsy but no additional clinical features. Ophthalmological examination revealed no abnormalities except for decreased thickness of the retinal nerve fiber layer. Audiometry showed mild sensorineural hearing impairment of both ears. Hormonal evaluation suggested isolated gonadotropin deficiency. Next-generation sequencing-based mutation screening of 13 major causative genes for HH identified a p.Lys35∗ mutation in SOX2 and excluded pathogenic mutations in other tested genes. The p.Lys35∗ mutation appeared to encode a non-functioning SOX2 protein that lacks 283 of 317 amino acids. The SOX2 mutation was absent in the maternal DNA sample, while a paternal sample was unavailable for sequence analysis. These results expand the clinical consequences of SOX2 haploinsufficiency to include non-syndromic HH. Systematic mutation screening using a next-generation sequencer and detailed evaluation of nonspecific ocular/neurological features may help identify SOX2 mutation-positive individuals among HH patients.