We describe the development and implementation of a neurofibromatosis type 2 (NF2) mutation scanning service
based on novel techniques. All 17 exons of the NF2 gene are amplified in four polymerase chain reaction
(PCR) reactions, using the meta-PCR technique to link the NF2 exons into chimeric concatamers. The meta-PCR products are then scanned for point mutations by direct sequencing. A four-exon dosage assay is used to
test for large deletion/duplication mutations. In certain cases when tumour studies are necessary, these techniques
are also combined with loss of heterozygosity analysis with three highly polymorphic microsatellite markers
located within or close to the NF2 gene. Over a period of 2 years, we have applied these techniques in a
service setting to the analysis of 271 patient samples (245 lymphocyte DNA; 26 schwannoma DNA). Meta-PCR
and sequencing identified 90 point mutations in the 271 blood and tumor samples, 48 of which have not been
reported previously. Dosage analysis identified large deletions in 12 of the lymphocyte DNA samples. In addition,
over 84% of mutations were identified in 23 schwannoma DNA samples in which complete analysis was
possible. Adoption of this novel strategy has increased the overall mutation detection rate in familial NF2 cases
to 88% and sporadic NF2 cases to 59%. It has also allowed us to decrease our reporting turnaround times,
and because of a low overall failure rate, permitted the running of an efficient and cost-effective service.
