The SUFU gene (OMIM*607035) encodes a component of the Sonic hedgehog (SHH)/Patched (PTCH) signalling pathway. Mutations in the SUFU gene are expected to result in the same clinical phenotype as mutations in the better known PTCH1 gene (OMIM*601309). Screening for the SUFU gene is therefore suggested when the PTCH1 gene is wildtype in patients with clinical basal cell nevus (Gorlin) syndrome (OMIM#109400). Germline mutations in the SUFU gene are suggested to predispose to infant desmoplastic/ nodular medulloblastomas, basal cell carcinomas and meningiomas. This SUFU susceptibility gene shows autosomal dominant inheritance with an incomplete penetrance. In addition to point mutations, both whole SUFU gene duplications and partial SUFU gene deletions have been described (Brugieres L et al. 2012, J Clin Oncol. 30:2087-93; Smith MJ et al. 2014, J Clin Oncol. 32:4155-61).
The SUFU gene (12 exons) spans ~129 kb of genomic DNA and is located on 10q24.32, 104 Mb from the p-telomere (HG18). The P472-A1 SUFU probemix contains one probe for each exon of the gene, with the exception of exons 3, 10 and 12 for which two probes per exon have been included. In addition, one probe for both the upstream and downstream genes of the SUFU gene are included. A total of 13 reference probes have been included in this probemix, detecting 13 different autosomal chromosomal locations which are relatively stable by copy number in both meningiomas and medulloblastomas, allowing analysis of tumour specimens for the SUFU gene.
This SALSA® MLPA® probemix is designed to detect deletions/duplications of one or more sequences in the aforementioned gene in a DNA sample. Heterozygous deletions of recognition sequences should give a 35-50% reduced relative peak height of the amplification product of that probe. Note that a mutation or polymorphism in the sequence detected by a probe can also cause a reduction in relative peak height, even when not located exactly on the ligation site! In addition, some probe signals are more sensitive to sample purity and small changes in experimental conditions. Therefore, deletions and duplications detected by MLPA should always be confirmed by other methods. Not all deletions and duplications detected by MLPA will be pathogenic; users should always verify the latest scientific literature when interpreting their findings. We have no information on what percentage of defects in these genes is caused by deletions/duplications of complete exons. Finally, note that most defects in this gene are expected to be small (point) mutations which will not be detected by this SALSA® MLPA® test.