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Autosomal recessive types of both syndromic and non-syndromic inherited myopia are common in Saudi Arabia (SA) because many people marry their relatives. The prevalence of syndromic myopathies in SA, like Stickler syndrome (SS), Knobloch syndrome (KS), and Marfan syndrome (MFS), further complicates the disease spectrum. The causative genes linked to the Knobloch, Marfan, and Pierson syndromes are COL18A1, FBN1, and LAMB2, respectively. Additionally, we found recessive types of non-syndromic high myopia that have a high chance of causing retinal detachment, like those linked to LRPAP1 and LEPREL1. In these cases, regular evaluation and early intervention, including prophylactic laser photocoagulation and pars plana vitrectomy, may improve the outcome. Advancements in genetic testing for diagnosis and prevention accelerate detection, facilitate early interventions, and provide genetic counseling. The utilization of artificial intelligence (AI), machine learning (ML), and the advancement of gene therapy offer promising avenues for personalized care. We place a high value on using genetic knowledge to create a national screening program and patient registry aimed at understanding the national burden of myopia, knowing that we have a high rate of consanguinity, which reflects pathogenic homozygous alleles and founder mutations. This initiative will incorporate genetic counseling and leverage innovative technologies, which are crucial for disease management, early identification, and prevention in Saudi Arabia’s healthcare system. Full article

Background/Objectives: Knobloch syndrome 1 (KS) is an autosomal recessive inherited ocular syndrome characterized by a combination of high myopia, vitreoretinal degeneration, and occipital encephalocele. KS is caused by biallelic pathogenic variants in the COL18A1 gene. Diagnosing KS can be challenging due to its clinical heterogeneity and the rarity of the syndrome. Methods: We conducted comprehensive clinical and instrumental ophthalmological examinations, whole-exome sequencing, Sanger sequencing, and segregation analysis to evaluate affected families. Results: Two patients presenting with high myopia, low visual acuity, chorioretinal atrophy, and occipital skin/skull defects were diagnosed with Knobloch syndrome 1 (KS). In Case 1, a 14-year-old boy, the COL18A1 variants identified were c.2673dup and c.3523_3524del in a compound heterozygous state. Case 2 involved a 3-year-old girl, the c.1637_1638dup and c.3523_3524del variants were identified in a compound heterozygous state. In Case 3, a retrospectively observed boy of 3 y.o. with KS, the variants c.929-2A>G and c.3523_3524del were defined earlier. Conclusions: We confirmed KS molecularly in two novel families. Additionally, in Case 3 of a retrospectively analyzed third family and in both novel cases, one of the biallelic causative variants was the same known 2bp deletion in exon 40 of the collagen XVIII gene. Cases 1 and 3 were characterized by connective tissue dysplasia features and a pathognomonic Knobloch triad. No neurological manifestations and no trends in the genotype–phenotype relationship were found. The heterogeneity of phenotype in the case series is likely to be the result of further factors and/or genetic background. Full article

Knobloch syndrome is an inherited disorder characterized by high myopia, retinal detachment, and occipital defects. Disease-causing mutations have been identified in the COL18A1 gene. This study aimed to investigate novel variants of COL18A1 in Knobloch syndrome and describe the associated phenotypes in Chinese patients. We reported six patients with Knobloch syndrome from four unrelated families in whom we identified five novel COL18A1 mutations. Clinical examination showed that all probands presented with high myopia, chorioretinal atrophy, and macular defects; one exhibited rhegmatogenous retinal detachment in one eye. Occipital defects were detected in one patient. Full article