Search

Mucolipidosis type IV (MLIV) is an autosomal recessively inherited lysosomal storage disorder characterized by progressive psychomotor delay and retinal degeneration that is associated with biallelic variants in the MCOLN1 gene. The gene, which is expressed in late endosomes and lysosomes of various tissue cells, encodes the transient receptor potential channel mucolipin 1 consisting of six transmembrane domains. Here, we described 14-year follow-up observation of a 4-year-old Japanese male MLIV patient with a novel homozygous in-frame deletion variant p.(F313del), which was identified by whole-exome sequencing analysis. Neurological examination revealed progressive psychomotor delay, and atrophy of the corpus callosum and cerebellum was observed on brain magnetic resonance images. Ophthalmologically, corneal clouding has remained unchanged during the follow-up period, whereas optic nerve pallor and retinal degenerative changes exhibited progressive disease courses. Light-adapted electroretinography was non-recordable. Transmission electron microscopy of granulocytes revealed characteristic concentric multiple lamellar structures and an electron-dense inclusion in lysosomes. The in-frame deletion variant was located within the second transmembrane domain, which is of putative functional importance for channel properties.

Aims/Introduction To determine the current clinical preferences of anti‐vascular endothelial growth factor (VEGF) treatment protocols for diabetic macular edema (DME) in Japan. Materials and Methods This was a descriptive cross‐sectional study. Answers to a questionnaire consisting of 16 questions were obtained from 176 of 278 (63.3%) surveyed ophthalmologists. Results The results showed that 81.2% preferred intravitreal injections of anti‐VEGF antibodies as the first‐line therapy. The most important indicators for beginning anti‐VEGF therapy were: the best‐corrected visual acuity in 44.3% and the retinal thickness in 30.7%. In the loading phase, 53.4% preferred a single injection, and in the maintenance phase, 75.0% preferred the pro re nata regimen. Financial limitation (85.8%) was reported as the most important difficulty in the treatment. For combination therapy with anti‐VEGF treatment, panretinal photocoagulation, focal photocoagulations and a sub‐Tenon steroid injection were preferred. The contraindications for anti‐VEGF therapy were: prior cerebral infarction (72.7%). Regarding the use of both approved anti‐VEGF agents in Japan, ranibizumab and aflibercept, 39.8% doctors used them appropriately. Conclusions Our results present the current clinical preferences of anti‐VEGF treatment for DME in Japan. The best‐corrected visual acuity and the retinal thickness are important indicators to institute this therapy. The majority of the ophthalmologists use anti‐VEGF treatment as first‐line therapy and prefer the 1 + pro re nata regimen.

Retinitis pigmentosa (RP) is an inherited blinding disease characterized by progressive loss of retinal photo-receptors. There are numerous rodent models of retinal degeneration, but most are poor platforms for interventions that will translate into clinical practice. The rabbit possesses a number of desirable qualities for a model of retinal disease including a large eye and an existing and substantial knowledge base in retinal circuitry, anatomy, and ophthalmology. We have analyzed degeneration, remodeling, and reprogramming in a rabbit model of retinal degeneration, expressing a rhodopsin proline 347 to leucine transgene in a TgP347L rabbit as a powerful model to study the pathophysiology and treatment of retinal degeneration. We show that disease progression in the TgP347L rabbit closely tracks human cone-sparing RP, including the cone-associated preservation of bipolar cell signaling and triggering of reprogramming. The relatively fast disease progression makes the TgP347L rabbit an excellent model for gene therapy, cell biological intervention, progenitor cell transplantation, surgical interventions, and bionic prosthetic studies.

The co-occurrence of skeletal dysplasia and ophthalmologic abnormality is extremely rare. We report on a boy of a unique form of spondylometaphyseal dysplasia associated with cone-rod dystrophy. He presented with postnatal severe short stature, progressive lower limb deformity with rhizomelic shortening of the long bones, prominent joints with limited mobility in knees and elbows, mild thoracic scoliosis, and vision impairment due to cone dystrophy. Correction of deformity and simultaneous limb lengthening was performed in bilateral femora and tibiae without major complications. Skeletal manifestations in addition to comprehensive ophthalmologic examinations were described in this patient who had been followed from infancy to 16 years of age.

The role of neuronal N-methyl-D-aspartate (NMDA) receptor-mediated intracellular signaling has been elucidated in both physiological and pathological conditions. However, the details of relative vulnerability for excitotoxicity remain unknown. Retinal excitotoxicity is involved in various diseases leading to irreversible blindness. Here, we used the visual system and explored the mechanistic details of the NMDA-elicited intracellular events, especially in the amacrine cells, which are the most vulnerable type of neuron in the retina. G-substrate, a specific substrate of cyclic guanosine 3′,5′-monophosphate (cGMP)-dependent protein kinase, is colocalized with amacrine cells and acts as an endogenous inhibitor of protein phosphatase. To elucidate how G-substrate was involved in NMDA-induced amacrine cell death, the immunohistochemical analysis with G-substrate antibody was performed following NMDA injury. In vivo, NMDA immediately decreased G-substrate immunoreactivity, and the suppression of calpain activation using ALLN or calpain III, an inhibitor of calpain, blocked this decrease. In vitro, degraded fragments of G-substrate were detected within 10 min after coincubation of G-substrate and calpain. Moreover, G-substrate knockout (G-substrate−/−) mice were more susceptible to NMDA injury than wild-type mice. ALLN did not have a neuroprotective effect in G-substrate−/− mice. These data strongly suggest that calpain-mediated loss of G-substrate represents an important mechanism contributing to NMDA-induced amacrine cell death. © 2008 Wiley-Liss, Inc.

The clinical presentation and electrophysiological findings are described of three consecutive cases with pericentral pigmentary retinal degeneration. The responses to bright flashes after dark adaptation showed negative waveform shape in all cases. Rod responses were strongly reduced compared with cone responses. Cone electroretinograms elicited by long-duration stimuli showed greater loss of the on-response than the off-response. The ratio of the on-response amplitude to off-response amplitude of these patients (0.52 +/- 0.12; mean +/- SD, n = 6) was significantly smaller than that of normal subject (0.83 +/- 0.21; mean +/- SD, n = 8) (Mann-Whitney U-test, P < 0.01). The electrophysiological findings of these cases suggest a greater defect of inner retinal function, especially in transmission between photoreceptors and depolarizing bipolar cells.

Occult macular dystrophy (OMD) is an unusual inherited or sporadic macular dystrophy characterized by an essentially normal appearing ocular fundus and normal ocular circulation determined by fluorescein angiography but with a progressive decrease of visual acuity. We present a family with OMD who have a delay in the implicit times of both the visual-evoked potentials and the pupillary light reflexes. Because these delays are usually indicative of optic nerve disorders, deciding on a diagnosis between OMD and optic nerve disorder should be done carefully. We are not aware of any studies that have reported these findings in patients with OMD.