An electrophysiological study on children and young adults with Alport's syndrome

Ocular Manifestations and Potential Treatments of Alport Syndrome: A Systematic Review

Objectives. Alport syndrome (AS) is a severe, rare hereditary disorder that can lead to end-stage renal disease, auditory degeneration, and ocular abnormalities. Despite extensive research on AS in relation to auditory and renal disorders, more research is needed on the ocular presentations of AS. This systematic review aims to summarize the common ocular abnormalities in patients with AS and to explore the potential treatment options for these irregularities. Methods. The PubMed, MEDLINE, and EMBASE databases were systematically searched from January 1977 to April 2022. Only papers that were published in the English language and explored the ocular abnormalities in AS patients were selected. We manually searched reference lists of included papers for additional studies. Results. A total of 23 articles involving 195 patients were included in this review. The common ocular manifestations in AS patients are lenticonus, macular holes, fleck retinopathy, and thinning of the macula. Although published literature has described the use of cataract surgeries and vitrectomies as standard surgical techniques to alleviate ocular abnormalities in non-AS patients, it must be noted that surgical techniques have not been evaluated in a large research study as a solution for AS abnormalities. Another prospective treatment for AS is gene therapy through the reversion of causative COL4 variants to wild type or exon-skipping therapy for X-linked AS with COL4A5 truncating mutations. Gene therapy, however, remains unable to treat alterations that occur in the fetal and early development phase of the disease. Conclusions. The review found no definitive conclusions regarding the efficacy and safety of surgical techniques and gene therapy in AS patients. Recognition of ocular abnormalities through an ophthalmic examination with an optical coherence tomography (OCT) and slit-lamp examination is critical to the medical field, as ophthalmologists can aid nephrologists and other physicians in diagnosing AS. Early diagnosis and care can minimize the risk of detrimental ocular outcomes, such as blindness and retinal detachment.

[Bilateral visual loss in a young male patient]

We present the case of a 36-year-old male patient who presented with an increasing bilateral loss of vision which had existed for several years. Slit-lamp examination revealed a conical anterior protusion of the lens and funduscopy showed a discreet perimacular dot and fleck retinopathy. In consideration of all clinical findings the patient was diagnosed with anterior lenticonus as an ocular manifestation of an Alport's syndrome which is a rare X-linked disease. Besides renal failure and hearing loss which occur early, ocular changes usually manifest later on. Patients with a anterior lenticonus can be effectively treated with phacoemulsification and intraocular lens implantation. The visual outcome after surgery is excellent.

Electron microscopic examination of the anterior lens capsule in a case of Alport's syndrome

PURPOSE

To report a case of Alport's syndrome and to present electronmicroscopic examination findings of the anterior lens capsule of this patient.

METHOD

A 21-year-old man was referred for low visual acuity and retinal pigment epithelial changes in the left eye. The patient and his relatives underwent detailed ophthalmological examination, including electrophysiological testing. The patient also underwent electronmicroscopic examination of the anterior lens capsule.

RESULTS

His visual acuity was 6/18 OD and 6/15 OS. Anterior lenticonus and subcapsular opacities were observed in the left eye. Cataract extraction by phacoemulsification with intraocular lens implantation was performed for his poor visual performance. During the capsulorhexis, the remarkably thin and fragile anterior capsule was noted and removed. Ultrastructural analysis of the anterior lens capsule showed a thinner central zone compared with the periphery.

CONCLUSIONS

The course of Alport's syndrome can be ameliorated by early diagnosis. Therefore, the ophthalmological examination of a patient with anterior lenticonus must be combined with a detailed medical evaluation. Ultrastructural analysis of the lens capsule can support the diagnosis of Alport's syndrome.

Alport syndrome: a review

Alport syndrome, a hereditary nephritis accompanied by high-tone sensorineural deafness and distinctive ocular signs was first noted in the literature during the early 1900s. This disease is caused by a genetic defect in Type IV collagen which makes up basement membranes in many body systems. The patient will usually have bilateral anterior lenticonus causing varied refractive errors. You may also note yellow-white to silver flecks within the macular and midperipheral regions of the retina. The treatment of the visual problems is an important but secondary concern due to the seriousness of the systemic disease. Dual sensory loss, however, creates an urgent need for appropriate vision care. Due to the high risk for developmental delay and decreased social integration, early intervention should be considered in the treatment plan. Coping strategies for the patient (and the family) need to be addressed because of the chronicity of this syndrome. The primary care optometrist will be challenged by the individual with Alport syndrome since a balance between oculo-visual, developmental/psycho-educational and systemic care is required. A multi-disciplinary approach by the healthcare management team will enhance the quality of life and positive outcomes for these patients.

Skin ERGs: their effectiveness in paediatric visual assessment, confounding factors, and comparison with ERGs recorded using various types of corneal electrode

Comparison of scotopic and photopic ERGs recorded using a variety of ERG electrodes show that contact lens electrodes produce the largest ERGs, and these are about 30-50% larger compared with those recorded with foil or thread electrodes, which contact a smaller part of the cornea. Flash ERGs recorded from infra-orbital skin electrodes are about one eighth the size of those recorded with contact lens electrodes, and around one quarter the size of those recorded with foil or fibre corneal electrodes. Reliable ERGs can be obtained in young children from infra-orbital electrodes sited centrally, within 1 cm of the rim of the eyelid, when signal averaging is used. Stimulation under fully darkened laboratory conditions with red and dim blue flashes permit assessment of cone and rod function, respectively. Factors such the recording electrode position, electrode derivation, upward rotation of the eye, eyelid closure and markedly constricted pupils can degrade the skin ERG. There are strong diagnostic advantages in recording the VEP concurrently with the skin ERG, particularly in young children. Examples of recordings in Leber's amaurosis, delayed visual maturation, albinism, optic nerve hypoplasia, achromatopsia add X-linked congenital stationary nightblindness are shown to demonstrate how ERG/VEP recordings can help in distinguishing between these conditions.