[A pseudo-outbreak of pharyngeal gonorrhoea related to a false-positive PCR-result]. / Een pseudo-uitbraak van keelgonorroe samenhangend met een fout-positieve PCR-uitslag.

Nucleic acid amplification tests, including the polymerase chain reaction (PCR), are sensitive and specific tests that are often used for diagnosing sexually transmitted diseases (STDs). A pseudo-outbreak of pharyngeal gonorrhoea in a group of prostitutes turned out to have been caused by false-positive test results due to commensal oropharyngeal Neisseria species. Specific molecular tests may yield erroneous results. When the results of an STD study have major consequences at a legal or social level, it is advisable, in consultation with a medical microbiologist, to take a sample for culture or to carry out a second molecular test aimed at a different part of the bacterial genome.

C-kit Asp-816-Val mutation analysis in patients with mastocytosis.

BACKGROUND: Mastocytosis is a heterogeneous group of disorders characterized by abnormal accumulation of mast cells. OBJECTIVE: Skin biopsies from 24 patients (23 with proven mastocytosis) were screened for the presence of the c-kit Asp-816-Val mutation. METHODS: In frozen biopsies, RNA was isolated, cDNA synthesis and PCR, the expected PCR product of 346 bp was obtained from 23 patients. RESULTS: In patients with urticaria pigmentosa, the mutation was detected in 38% of the adults and 25% of the children. With regard to the clinical presentation of the disease, no difference was found between adult patients with and without the mutation, as detected with our assay. One out of the 2 children with the mutation had an atypical presentation of the disease. CONCLUSION: the mutation could not be detected in all the patients, probably due to lack of sensitivity of the methods.