Leber Congenital Amauroi–A Model for Efficient Genetic Teting of Heterogeneou Diorder: LXIV Edward Jackon Memorial Lecture

Purpoe To critically evaluate our experience in molecular teting of Leber congenital amauroi (LCA) and to ue thi information to devie a general approach to heterogeneou receive diorder. Careful clinical and molecular characterization of large cohort of patient affected with inherited eye dieae will be an eential tep in the development of effective therapy for thee dieae, epecially when the therapy involve gene replacement. Deign A molecular genetic cae-control tudy. Method ix hundred forty-two unrelated individual with the clinical diagnoi of LCA and 200 unrelated control individual were creened for dieae-cauing equence variation in eight gene uing variou combination of ingle-trand conformational polymorphim analyi (CP), automated DNA equencing, multiplex allele-pecific ligation analyi (NPlex), and high-denity olid-phae ingle nucleotide polymorphim genotyping. Reult Four hundred forty intance of 189 different dieae-cauing equence variation were oberved in thi tudy, 98 of which have not been previouly reported. One hundred forty-ix of the 189 variation (77%) were oberved in only a ingle individual. The oberved variation were not evenly ditributed among the LCA patient or among the eight gene. Empirical analyi of thi uneven ditribution wa ued to devie a multi-platform mutation detection trategy that i four time more efficient than a more conventional trategy of completely equencing all of the coding region of all LCA gene in all ubject. Hardy-Weinberg analyi of the oberved mutation ugget that thee eight gene are collectively reponible for about 70% of the cae of LCA in North America. The carrier frequency of the mot common LCA allele (an intron 26 variation in CEP290) wa found to be 2/3,248, which ugget that the overall prevalence of LCA in thi population i about 1/81,000. An allele-pecific ligation aay (NPlex) wa deigned to detect 68 of the mot common LCA-cauing allele, and emi-quantitative analyi of the data from thi aay alo revealed example of gene deletion and iodiomy in the cohort. Concluion The data demontrate that a tiered creening trategy combining allele-pecific detection with automated DNA equencing can increae the efficiency of autoomal receive mutation detection four-fold when compared with DNA equencing alone. However, the very high rate of unique mutation oberved in thi tudy (77%) ugget that DNA equencing will remain an important part of the overall trategy if high enitivity i to be achieved.