Delayed diagnosis of oculopharyngeal muscular dystrophy in Scotland.

INTRODUCTION: Oculopharyngeal muscular dystrophy (OPMD) presents with progressive ptosis, dysphagia and limb girdle weakness, and is caused by expansion of a trinucleotide tandem repeat within the gene encoding poly-(A) binding protein 2. AIM: To review the clinical manifestations of all genetically confirmed patients with OPMD in Scotland identified since 2002, and to estimate the delay between symptom onset and diagnosis. Method Retrospective case note review. RESULTS: The authors identified 17 patients. The commonest first symptom was ptosis at about the age of 60 years. Three to 20 years elapsed from the onset of ptosis to OPMD diagnosis. In 14 (82%) patients, dysphagia had developed by the time of diagnosis, and four (24%) out of these 14 patients with dysphagia had undergone a decade of investigation and treatment for pharyngeal problems. Thirteen patients (77%) also had symptoms of limb girdle muscle weakness. Every patient had a first-degree relative with ptosis. CONCLUSIONS: OPMD could have been diagnosed earlier in every patient in this case series. Greater awareness of OPMD among ophthalmologists, gastroenterologists and otolaryngologists may lead to earlier diagnosis, improved management and avoidance of unnecessary investigations.

Two cases of oculopharyngeal muscular dystrophy (OPMD) with the rare PABPN1 c.35G>C; p.Gly12Ala point mutation.

Oculopharyngeal muscular dystrophy is a neuromuscular disease usually presenting in the 5th or 6th decades of life with a dominant inheritance pattern. In almost all cases the cause of the disease is the expansion of a DNA repeat sequence containing GCG and GCA codons in exon 1 of the PABPN1 gene from 10 to between 12 and 17 repeats. However one case has been previously reported without the gene expansion but instead with a c.35G>C missense mutation converting a glycine codon to an alanine and resulting in a sequence of 13 contiguous alanine codons, thus mimicking the effect of the common expansion mutation. Here we report two further cases of OPMD caused by the c.35G>C point mutation. Clinical and pedigree data indicate the usual OPMD dominant inheritance pattern.

Chromosomal changes in colorectal adenomas: relationship to gene mutations and potential for clinical utility.

Although the occurrence of both chromosomal aberrations and specific gene mutations in colorectal tumorigenesis is firmly established, the relationship between these different forms of genetic abnormality remains poorly understood. We have previously demonstrated, in colorectal adenocarcinomas, that mutations of APC, KRAS, and TP53 are each specifically associated with certain chromosomal aberrations. Using comparative genomic hybridization and mutational analysis of APC, KRAS, and TP53 to evaluate 78 colorectal adenomas, we have shown that several of the significant relationships between gene mutations and chromosomal abnormalities reported in colorectal adenocarcinomas also exist at the adenomatous stage. KRAS mutation correlated with 12p gain (P < 0.001) and TP53 mutation with both 20q gain and 18q loss (P = 0.03 for both). In addition, we have identified two chromosomal aberrations, gain of 13q and loss of 11q, that correlate with the presence of synchronous adenomas (P = 0.049 and P = 0.03, respectively) and several chromosomal changes (20p+, 20q+, 17p-, and 18q-) that are related to the onset of high-grade dysplasia. These data strengthen our previous contention that the co-occurrence of specific gene mutations and chromosomal changes is not random and significant relationships do exist. Our findings also raise the possibility that certain chromosomal aberrations may act as important clinical biomarkers.