Patients with primary cataract as a genetic pool of DMPK protomutation.
Myotonic dystrophy 1 (DM1) is known to diminish reproductive fitness in its severe form. Since no de novo mutations are known for this disease, it has the tendency to become extinct from a population. To explain the preservation of DM1 in a population, a hypothesis that a pool of subjects for the mutated gene exists in the apparently healthy (non-DM1) population was tested. In order to determine the (CTG) repeat number, PCR was performed in 274 patients found to have primary cataract of adult onset who showed no DM1 symptoms, and were not related to DM1 patients. In four cataract patients (1.46%; 95% CI 0.5-3.7), a protomutation in the myotonin protein kinase gene was found which might lead to a complete mutation after transmission through the next generations. The number of (CTG) repeats in the remaining 270 cataract patients did not differ significantly from the control subjects in terms of the distribution of larger [(CTG)n > or = 19] versus smaller [(CTG)n < 19] alleles. We consider the primary cataract patients to be the pool of DMPK protomutation from which DM1 mutation is maintained in the population.
Medica
Igor
I
Division of Medical Genetics, Department of Obstetrics and Gynaecology, University Medical Centre Ljubljana, Šlajmerjeva 3, 1000, Ljubljana, Slovenia.|Outpatient Paediatric Clinic Pula, Pula, Croatia.
Teran
Natasa
N
Division of Medical Genetics, Department of Obstetrics and Gynaecology, University Medical Centre Ljubljana, Šlajmerjeva 3, 1000, Ljubljana, Slovenia.
Volk
Marija
M
Division of Medical Genetics, Department of Obstetrics and Gynaecology, University Medical Centre Ljubljana, Šlajmerjeva 3, 1000, Ljubljana, Slovenia.
Pfeifer
Vladimir
V
Department of Ophtalmology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
Ladavac
Edi
E
Department of Ophtalmology, General Hospital Pula, Pula, Croatia.
Peterlin
Borut
B
Division of Medical Genetics, Department of Obstetrics and Gynaecology, University Medical Centre Ljubljana, Šlajmerjeva 3, 1000, Ljubljana, Slovenia. borut.peterlin@guest.arnes.si.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002386:Cataract / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009223:Myotonic Dystrophy / Q000235:genetics*; D065636:Myotonin-Protein Kinase; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
C585517:DMPK protein, human; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases