Perrault et al. (1996) conducted genetic analysis for all sibs with Leber congenital amaurosis in two consanguineous Arab-Algerian families and found homozygosity for a T>C transition in exon 8 at nucleotide 1767 of the GUC2D gene.

Soens et al. (2016) reported on a 5-year-old Saudi boy with LCA.  At 6-months of age, the child’s vision was found to be limited to light perception.  He also suffered from nystagmus, the oculo-digit sign and an absent electroretinogram.  Whole exome sequencing found that the patient’s CLUAP1 gene contained a homozygous non-synonymous mutation c.817C>T (c.319C>T in the short isoform), resulting in a p.L273F substitution at a highly conserved residue within the coiled-coil domain (p.L107F in the short isoform).  Functional studies found that the mutation was highly hypomorphic and resulted in a CLUAP1 protein with only 5% of the activity of the wildtype. 

Safieh et al., (2016) described a 6-month old Saudi girl with Leber congenital amaurosis.  She was born to consanguineous parents and was noticed to have rapid synchronous eye movements of both eyes at 40-days of age.  Clinical examination after 18-months showed classical oculodigital sign, moderate bilateral enophthalmos, irregular nystagmus, mild neuro-epithelial atrophy, and mild retinal vascular attenuation.  A novel pathogenic missense mutation in the GUCY2D gene was identified in the patient.  The authors concluded that this mutation expanded the genotypic spectrum of congenital retinal dystrophies in the Saudi population.

Perrault et al. (1996) conducted a genetic analysis for three families from Tunisia with Leber congenital amaurosis. The first family was a Jewish Sephardi family in which affected members were homozygous for a 1-bp deletion (c.460delC) in exon 2 at nucleotide 460 of GUC2D. The second family was of Arab Tunisian origin. Affected members were homozygous for a 1-bp deletion in exon 2 at nucleotide 693 (693delC) of GUC2D. In the third family, a consanguineous Arab Tunisian family, all sibs had homozygosity for a G>T transversion at nucleotide 227 of GUC2D.