Korean J Lab Med.  2010 Apr;30(2):190-194. 10.3343/kjlm.2010.30.2.190.

Molecular Characterization of the NF2 Gene in Korean Patients with Neurofibromatosis Type 2: A Report of Four Novel Mutations

• Seong MW
• Yeo IK
• Cho SI
• Park CK
• Kim SK
• Paek SH
• Kim DG
• Jung HW
• Park H
• Kim SY
• Kim JY
• Park SS

• KMID: 1096807
• DOI: http://doi.org/10.3343/kjlm.2010.30.2.190

Abstract

BACKGROUND
Neurofibromatosis type 2 (NF2) is an autosomal dominant syndrome caused by the NF2 tumor suppressor gene. However, the NF2 mutation characteristics in Korean patients are not sufficiently understood. In this study, we conducted a comprehensive mutational analysis in 7 Korean NF2 patients by performing direct sequencing and gene-dosage assessment.
METHODS
We analyzed all exons and flanking regions of NF2 by direct sequencing and screened the deletions or duplications involving NF2 by multiplex ligation-dependent probe amplification.
RESULTS
Four novel NF2 mutations, including 2 splice-site mutations (c.364-1G>A and c.886-3C>G), 1 frameshift mutation (c.524delA), and 1 missense mutation (c.397T>C; p.Cys133Arg), were identified in our patients. No large deletion or duplication was identified in our series. Subsequently, we identified an abnormal splicing product by using reverse transcription-PCR and direct sequencing in 2 patients with a novel splice-site mutation. The missense mutation c.397T>C was predicted to have harmful effects on protein function.
CONCLUSIONS
The detection rate of NF2 mutations in Korean patients (57%) is similar to those in other populations. Our results provided a greater insight into the mutational spectrum of the NF2 gene in Korean subjects.

Keyword

Hereditary cancer; Neurofibromatosis type 2; NF2

MeSH Terms

3' Flanking Region/genetics
5' Flanking Region/genetics
Adult
Aged
Amino Acid Sequence
Asian Continental Ancestry Group/*genetics
Child, Preschool
Exons
Female
Frameshift Mutation
*Genes, Neurofibromatosis 2
Humans
Male
Middle Aged
Molecular Sequence Data
*Mutation
Mutation, Missense
Neurofibromatosis 2/diagnosis/*genetics
RNA Splice Sites
Republic of Korea
Sequence Analysis, DNA
Young Adult

Figure

• 

  Fig. 1. Results of RT-PCR and sequence analysis for the 2 splice-site mutations c.364-1G>A (patient P4) and c.886-3C>G (patient P2). (A) The c.364-1G>A mutation yields a 0.55-kb abnormal product as well as 0.63-kb normal product in RT-PCR with the following primers: F-5′-AAGCAACCCAAGACGTTCAC-3′, R-5′-CCGGATTGCAAAGTAGTTCA-3′. (B) The c.886-3C>G cannot be discriminated from normal products by using following primers: F-5′-CTGACCCCCAAGATCTCCT-3′, R-5′-GCTTCAGCTGATCTGCCTCT-3′. (C) Exon 4 skipping is shown in the cDNA sequence of patient 4 with c.364-1G>A. (D) Patient P2 is heterozygous for c.886-3C>G, and 2-bp insertion of AG (blue) between exon 9 (yellow) and exon 10 (pink) is shown in the cDNA sequence. This insertion is caused by the introduction of a new splice acceptor site from c.886-4A to c.886-3C>G and subsequent inclusion of original splice acceptor site (c.886-2_-1AG) in the mature transcript.

• 

  Fig. 2. Multiple alignment and amino acid conservation for a novel missense mutation c.397T>C (p.Cys133Arg). The cysteine at codon 133 is well-conserved among various species.

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