Loss of podocalyxin causes a novel syndromic type of congenital nephrotic syndrome

Many cellular structures directly imply specific biological functions. For example, normal slit diaphragm structures that extend from podocyte foot processes ensure the filtering function of renal glomeruli. These slits are covered by a number of surface proteins, such as nephrin, podocin, podocalyxin and CD2AP. Here we report a human patient presenting with congenital nephrotic syndrome, omphalocele and microcoria due to two loss-of-function mutations in PODXL, which encodes podocalyxin, inherited from each parent. This set of symptoms strikingly mimics previously reported mouse Podxl(−/−) embryos, emphasizing the essential function of PODXL in mammalian kidney development and highlighting this patient as a human PODXL-null model. The results underscore the utility of current genomics approaches to provide insights into the genetic mechanisms of human disease traits through molecular diagnosis.

Ultra-rare Disease and Genomics-Driven Precision Medicine

Since next-generation sequencing (NGS) technique was adopted into clinical practices, revolutionary advances in diagnosing rare genetic diseases have been achieved through translating genomic medicine into precision or personalized management. Indeed, several successful cases of molecular diagnosis and treatment with personalized or targeted therapies of rare genetic diseases have been reported. Still, there are several obstacles to be overcome for wider application of NGS-based precision medicine, including high sequencing cost, incomplete variant sensitivity and accuracy, practical complexities, and a shortage of available treatment options.

Ocular Abnormality of Korean Patients with Molecular Genetically Confirmed Gaucher Disease

PURPOSE: To investigate the ophthalmologic manifestations of Korean patients with Gaucher disease. METHODS: Clinical records of 5 patients who were referred to the pediatric ophthalmology clinic of Seoul National University Bundang Hospital after diagnosis of Gaucher disease at the genetics clinic of Ajou University Hospital between 2007 and 2008 were retrospectively reviewed. RESULTS: Five patients with type 3 Gaucher disease had hepatosplenomegaly and oculomotor apraxia, and 4 patients had growth and developmental delay. The most commonly detected genetic mutation was L444P. In addition, P201H, F2131, R257Q, and D315E+Rec 1b were identified. Five patients had oculomotor apraxia and limitation of abduction, and 4 patients had esotropia. One of the 4 patients who showed combined limitation of abduction, oculomotor apraxia, and esotropia, yet did not have growth and developmental delay. CONCLUSIONS: Most of the patients who were referred for ocular motor abnormalities with Gaucher disease showed a limitation of abduction, oculomotor apraxia, and esotropia. In patients with a limitation of abduction, oculomotor apraxia, and esotropia, Gaucher disease should be considered. Ophthalmologic examination is essential for subtyping and prognosing Gaucher disease.

Current Smoking Is Associated with a Poor Visual Acuity Improvement after Intravitreal Ranibizumab Therapy in Patients with Exudative Age-Related Macular Degeneration

In this study, the risk factors that may influence visual improvement after intravitreal ranibizumab (IVR) treatment for exudative age-related macular degeneration (AMD) were examined. From 2008 to 2012, 420 patients (448 eyes) with exudative AMD were prospectively registered at Seoul National University Hospital. From this group of patients, 125 eyes were included in this study. All patients were treated with 3 consecutive IVR injections. The visual acuity (VA) was evaluated at baseline and 1 month after the third ranibizumab injection. To evaluate the risk factors associated with VA improvement after IVR, patient demographic data and systemic risk factors were analyzed. Patients were divided into a poor VA improvement group and a good VA improvement group, with reference to the median visual improvement in all eyes. Among 125 eyes, 66 eyes (52.8%) were included in the responder group and 59 eyes (47.2%) in the non-responder group. The median VA improvement after 3 monthly ranibizumab injections was -0.05 logMAR. Multivariate analyses revealed that current smoking (adjusted OR, 7.540; 95% CI, 1.732-32.823) was independently associated with poor VA improvement after IVR treatment for exudative AMD. In conclusion, cigarette smoking is an independent risk factor for lower VA gains with IVR treatment for exudative AMD.

Leber's Hereditary Optic Neuropathy in a Patient Diagnosed With Normal Tension Glaucoma: A Case Report

PURPOSE: Leber's hereditary optic neuropathy (LHON) is caused by point mutations in mitochondrial DNA. The authors report a case of a middle-aged man with genetically confirmed LHON, combined with bilateral normal tension glaucoma (NTG). CASE SUMMARY: A 48-year-old man presented with complaints of decreased visual acuity in his left eye. His corrected visual acuity was 20/16 in the right eye and 20/63 in the left eye. The fundus photographs revealed a bilateral, superotemporal and inferotemporal retinal nerve fiber layer defect, corresponding to his visual field defect. The patient was diagnosed with bilateral NTG. After 2 months, the patient's corrected visual acuity in the left eye worsened to counting fingers and a central visual field defect was noticed in the Humphrey visual field test in the left eye. At 4 months after the initial visit, his corrected visual acuity in the right eye became 20/100, and the Goldmann visual field test demonstrated cecocentral scotoma. The fundus photographs showed a papillomacular bundle defect in his left eye. At 7 months after the initial visit, his visual acuity was hand movement in the right eye and a finger count in the left eye. A series of LHON gene mutation tests revealed a 11778 mitochondrial gene mutation, and the patient was diagnosed with LHON. CONCLUSIONS: Proper diagnosis of LHON might be disturbed by atypical manifestation of other optic nerve diseases, such as glaucoma. Therefore, suspecting LHON and checking for gene mutations as part of the work-up in patients with bilateral optic neuropathy is critical.