Molecular and phenotypic investigation of a New Zealand cohort of childhood-onset retinal dystrophy.

Inherited retinal diseases are clinically heterogeneous and are associated with nearly 300 different genes. In this retrospective, observational study of a consecutive cohort of 159 patients (134 families) with childhood-onset (<16 years of age) retinal dystrophy, molecular investigations, and in-depth phenotyping were performed to determine key clinical and molecular characteristics. The most common ocular phenotype was rod-cone dystrophy in 40 patients.

Analysis of the ABCA4 c.[2588G>C;5603A>T] Allele in the Australian Population.

Inherited retinal diseases (IRDs) are genetically and phenotypically diverse, and they cause significant morbidity worldwide. Importantly, IRDs may be amenable to precision medicine strategies, and thus the molecular characterisation of causative variants is becoming increasingly important with the promise of personalised therapies on the horizon. ABCA4, involved in the translocation of visual cycle derivatives, is a well-established, frequent cause of IRDs worldwide, with pathogenic variants implicated in phenotypically diverse diseases.

A founder deletion in the gene associated with congenital stationary night blindness and myopia is highly prevalent in Ashkenazi Jews.

Congenital stationary night blindness (CSNB) is a disease affecting the night vision of individuals. Previous studies identified as a gene involved in reduced night vision. Homozygous deletion of was the cause of CSNB in several children in 6 Ashkenazi Jewish families, thereby prompting further investigation of the carrier status within the families as well as in large cohorts of unrelated Ashkenazi and Sephardi individuals.

Variants in the gene in a Brazilian population with Stargardt disease.

Purpose: The aim of this study was to analyze and report pathogenic variants in the gene in Brazilian patients with a clinical diagnosis of Stargardt disease.

Methods: This retrospective study evaluated variants in the gene in Brazilian patients with Stargardt disease. The patients' visual acuity and age of symptom onset were obtained from previous medical records.

Detailed genetic characteristics of an international large cohort of patients with Stargardt disease: ProgStar study report 8.

Background/aims: To describe the genetic characteristics of the cohort enrolled in the international multicentre progression of Stargardt disease 1 (STGD1) studies (ProgStar) and to determine geographic differences based on the allele frequency.

Methods: 345 participants with a clinical diagnosis of STGD1 and harbouring at least one disease-causing ABCA4 variant were enrolled from 9 centres in the USA and Europe. All variants were reviewed and analysis was performed including allele frequency in public databases and pathogenicity predictions.

Novel Complex ABCA4 Alleles in Brazilian Patients With Stargardt Disease: Genotype-Phenotype Correlation.

Purpose: To analyze the presence of complex alleles of the ABCA4 gene in Brazilian patients with Stargardt disease and to assess the correlation with clinical features.

Methods: This was an observational cross-sectional study. Patients with a diagnosis of Stargardt disease who presented three pathogenic variants of the ABCA4 gene or who had variants previously described as complex alleles were included.

The Effect on Retinal Structure and Function of 15 Specific ABCA4 Mutations: A Detailed Examination of 82 Hemizygous Patients.

Purpose: To determine the effect of 15 individual ABCA4 mutations on disease severity.

Methods: Eighty-two patients harboring 15 distinct ABCA4 mutations in trans with null (hemizygous), 10 homozygous, and 20 nullizygous patients were recruited. Age of onset was determined from medical histories.

Phenotype and Progression of Retinal Degeneration Associated With Nullizigosity of ABCA4.

Purpose: We describe the phenotypes associated with nullizigosity and nine splicing mutations in the ABCA4 gene.

Methods: The study included 19 patients with biallelic null mutations (Group A, nullizygous), 27 with splicing mutations in the homozygous state or in trans with a null mutation (Group B), and 20 with p.G1961E in trans with a null mutation (Group C, control).

Progress and prospects of next-generation sequencing testing for inherited retinal dystrophy.

Next-generation sequencing, also known as massively paralleled sequencing, offers an unprecedented opportunity to study disease mechanisms of inherited retinal dystrophies: a dramatic change from a few years ago. The specific involvement of the retina and the manageable number of genes to sequence make inherited retinal dystrophies an attractive model to study genotype-phenotype correlations. Costs are reducing rapidly and the current overall mutation detection rate of approximately 60% offers real potential for personalized medicine and treatments.

The current status of molecular diagnosis of inherited retinal dystrophies.

Purpose Of Review: We are witnessing lightning-fast advances in the molecular diagnosis of inherited retinal dystrophies, mainly due to the widespread use of next-generation sequencing technologies. The purpose of this review is to highlight the breadth of findings from this in-depth testing approach, and to propose changes to our traditional testing and diagnostic paradigms. Lessons learned from modern molecular testing suggest that the previous concept of inherited retinal dystrophies as a group of 'single gene diseases' may require a significant update.

A useful multi-analyte blood test for cerebrotendinous xanthomatosis.

Objectives: Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder of bile acid (BA) synthesis that can cause progressive neurological damage and premature death. Blood (normally serum or plasma) testing for CTX is performed by a small number of specialized laboratories, routinely by gas chromatography-mass spectrometry (GC-MS) measurement of elevated 5α-cholestanol. We report here on a more sensitive biochemical approach to test for CTX particularly useful for confirmation of CTX in the case of a challenging diagnostic sample with 5α-cholestanol that, although elevated, was below the cut-off used for diagnosis of CTX (10 μg/mL or 1.

A blood test for cerebrotendinous xanthomatosis with potential for disease detection in newborns.

Cerebrotendinous xanthomatosis (CTX) is a rare, difficult-to-diagnose genetic disorder of bile acid (BA) synthesis that can cause progressive neurological damage and premature death. Detection of CTX in the newborn period would be beneficial because an effective oral therapy for CTX is available to prevent disease progression. There is no suitable test to screen newborn dried bloodspots (DBS) for CTX.