Knobloch Syndrome (KS) is a rare autosomal recessive hereditary disease. Despite its clinical heterogeneity, it is characterized by vitreoretinal degeneration and high myopia, with or without occipital skull defects. It is caused by mutations in the COL18A1 gene, which codifies for collagen XVIII, present in retina and vascular endothelium. Since the first description of the disease by doctors Knobloch and Layer in 1972, over 100 cases and 20 pathogenic or likely pathogenic mutations have been reported. We present the case of a child born from a consanguineous couple in Chile with congenital high myopia and dysmorphisms without an occipital skull defect. Whole exome sequencing analysis revealed an inherited homozygous variant in COL18A1, c.4224_4225delinsC, p.Pro1411Leufs*35.

The Duane-Radial Ray syndrome or Okihiro syndrome belongs to the SALL4-Related Disorders, a phenotypic spectrum, that additionally includes, acrorenoocular syndrome and Holt-Oram syndrome, caused by the alteration of the same gene, which has signifi cant relevance in the mesoderm, the limbs, and the heart development. These syndromes are characterized by thumb alteration, radial deviation of the forearm, Duane anomaly, and variable involvement of other organs such as kidney or heart. The prevalence is unknown. This is a case report of a Chilean patient with a pathogenic variant that confi rms the Duane Radial Ray syndrome previously not described in the population.