Abstract
Purpose:
To investigate the clinical features and perform a genetic analysis of an Egyptian family with dominant rhegmatogenous retinal detachment and high myopia.
Methods:
Five members of an Egyptian family with autosomal dominant rhegmatogenous retinal detachment and high myopia were examined clinically. Peripheral blood samples were collected and genomic DNA was extracted from blood leukocytes using standard techniques.All 54 exons, promoter and intron-exon junctions of COL2A1 gene were PCR amplified, and both forward and reverse strands were sequenced with the Sanger sequencing technique.
Results:
Features of Stickler syndrome type I (arthro-ophthalmopathy) were recognized in three members of the family with a dominant inheritance pattern. All the affected patients (the 38-year-old father, 7-year-old son, and 5-year-old daughter) had bilateral high myopia with membranous vitreous liquefaction, micrognathia and flattened facial appearance. Two of them, the father and 7-year-old son suffered from bilateral rhegmatogenous retinal detachment. The father had retinal detachment surgery done in the left eye by the second decade of life. His right eye passed into atrophia due to neglected long-standing retinal detachment. The 7-year-old son had corrective surgery for a cleft soft palate and claw feet done during the first year of his life. By the age of 6, he needed surgery for bilateral retinal detachment. The unaffected mother and the unaffected 1.5-year-old son had a normal general and ophthalmic examination. We identified a novel heterozygous C to T substitution in exon 24 at position 1558 of the cDNA sequence of COL2A1 (Ensembl: ENST00000380518). This [c. 1558C>T] causes a premature stop codon to replace Glutamine amino acid (Q) at position 520 [p. Q520X], potentially truncating 967 amino acids from the protein. This mutation was found in all three affected members of the family and was not in the two unaffected members nor in 46 Egyptian and 96 Caucasian controls.
Conclusions:
We identified a novel heterozygous nonsense mutation [p.Q520X] of the COL2A1 gene segregating in an Egyptian family with Stickler syndrome. To our knowledge, this mutation has not been previously reported.
Keywords: 604 mutations •
539 genetics