CYP1B1 gene analysis and phenotypic correlation in Portuguese children with primary congenital glaucoma.

PURPOSE

To investigate the prevalence of CYP1B1 mutations in Portuguese children with primary congenital glaucoma (PCG) and to study the possible correlations between the mutation status and clinical features of the disease.

METHODS

DNA sequencing analysis of the CYP1B1 gene was used to screen 21 children with PCG followed on Paediatric Ophthalmology and Medical Genetics consultations at D. Estefânia's Hospital (Centro Hospitalar de Lisboa Central, Portugal). The effect of mutations on the phenotype of the patients was also assessed. Presence and type of mutations in CYP1B1 gene, age at diagnosis, bilaterality, age at first surgery, postoperative intraocular pressure and corneal diameter, final visual acuity, number of surgical reinterventions, and number of antiglaucoma medications required postoperatively were noted.

RESULTS

Mutations in the CYP1B1 gene in 6 patients (28.57%) were detected, all compound heterozygotes. Seven types of mutations were identified: c.182G>A, c.317C>A, c.535delG, c.1064_1076del, c.1159G>A, c.1310C>T, and c.1390dupT. All patients with these mutations developed bilateral PCG, whereas in the group without mutations only 7 (46.67%) showed bilateral disease. Age at diagnosis was lower in the group of patients with these mutations (0.0 ± 0.00 vs 4.5 ± 2.63 months, p<0.01). In the remaining variables (age at first surgery, postoperative intraocular pressure and corneal diameter, final visual acuity, number of surgical reinterventions and antiglaucoma medications required postoperatively), no significant differences between the groups were detected (p>0.05 for all comparisons).

CONCLUSIONS

This study is the first to report the variety of mutations in the CYP1B1 gene in a group of Portuguese children with PCG and to describe 2 new mutations. Genetic analysis of PCG must be carried out, although it has not yet been possible to establish a genotype-phenotype correlation, with the exception of bilaterality and early age at diagnosis.