Intronic splicing mutations in PTCH1 cause Gorlin syndrome.

Area of Science:

• Genetics
• Molecular Biology
• Oncology

Background:

• Gorlin syndrome is an autosomal dominant disorder.
• Characterized by basal cell carcinoma, keratocysts, and skeletal abnormalities.
• Caused by heterozygous mutations in the PTCH1 tumor suppressor gene.

Purpose of the Study:

• To investigate PTCH1 mutations in Gorlin syndrome patients.
• To identify mutations missed by routine genetic testing.
• To improve the diagnostic rate of Gorlin syndrome.

Main Methods:

• RNA analysis on lymphocytes from ten Gorlin syndrome patients.
• Exonic sequencing and MLPA were previously performed.
• Genomic DNA sequence analysis was conducted.

Main Results:

• Two altered PTCH1 transcripts were identified.
• An intron 7 mutation (c.1068-10T>A) caused a frameshift.
• A deep intronic mutation (c.2561-2057A>G) led to a premature stop codon.

Conclusions:

• RNA analysis is crucial for detecting intronic PTCH1 mutations.
• These mutations cause loss of PTCH1 function.
• Enhanced genetic testing improves Gorlin syndrome diagnosis.