| Objectives: Screening the sequence of candidate gene to identify thevirulence gene and the mutant site of three Chinese congenital cataractfamilies (CAT-001, CAT-002and CAT-003). Clarify the pathogenic molecularbasis of these three ADCC families.Methods: Collect three Chinese congenital cataract families for thisstudy. detailed clinical examination for the family members to determinethe phenotype of cataract. Extract and purify the genomic DNA fromperipheral blood of proband via Wizard Genomic DNA Purification kit. Thecandidate mutation hotspot regions of ten cataract-causing genes arePCR-based sequenced directly in three families. Once any interestingsequence variation suggestive of a mutation be found in the proband, itwill later confirmed in parents and available relatives.Results: Morbidity of these three congenital cataract families arehigher than the general population. The affected member appears on eachgeneration without sex difference. The patients in first family CAT-001were born with congenital nuclear cataract．There is a missense mutation(c.C70A) on the exon2of CRYGD genes and results in threonine substitutionof proline at codon24of the encoding protein（p.P24T）. The patientsin second family CAT-002were born with congenital zonularcataract．Direct gene sequencing showed a G>A transition at the splicesite of intron3(IVS3+1G>A) of the betaA1-crystallin gene (CRYBA1) inthis family, this mutation influence the editing and splicing of hnRNAand due to cataract in finally. The patients in third family CAT-003wereborn with congenital nuclear cataract. Mutation analysis of the CRYBA1gene identified a3-bp deletion in272-274. It resulted in the deletionof glycine at codon91(DeltaG91). Conclusion: Pedigree analysis show that the mode of inheritance ofthese three families are autosomal dominant trait．The phenotype ofCAT-001is congenital nuclear cataract, CRYGD(p.P24T) is the geneticbasis of this family; The phenotype of CAT-002is congenital zonuralcataract, CRYBA1(IVS3+1G>A) is the genetic basis of this family; Thephenotype of CAT-003is congenital nuclear cataract, CRYBA1(DeltaG91) isthe genetic basis of this family. |
