Improvement of the diagnostic procedure in proximal myotonic myopathy/myotonic dystrophy type 2.
Proximal myotonic myopathy/myotonic dystrophy type 2 (PROMM/DM 2) is caused by an expansion of the (TG)n(TCTG)n(CCTG)n repeat tract in intron 1 of the ZNF9 gene located on chromosome 3q21. Because these expansions show a marked mitotic instability, expanded alleles are often difficult to detect. In order to improve the diagnostic procedure, we applied a combination of pulsed-field gel electrophoresis and semi-quantitative Southern blot analysis with a novel hybridization probe. The combination of these methods led to unequivocal results in about 98% of cases with a clinical diagnosis of PROMM/DM 2. Furthermore, we report the genotype/phenotype correlation in a patient lacking a normal ZNF9 allele and a further proband with a "grey zone" allele.
Jakubiczka
Sibylle
S
Institut für Humangenetik, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany. sibylle.jakubiczka@medizin.uni-magdeburg.de
Vielhaber
Stefan
S
Kress
Wolfram
W
Küpferling
Peter
P
Reuner
Ulrike
U
Kunath
Bernhard
B
Wieacker
Peter
P
D000328:Adult; D000368:Aged; D015139:Blotting, Southern; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020967:Myotonic Disorders / Q000175:diagnosis* / Q000235:genetics*; D009223:Myotonic Dystrophy / Q000175:diagnosis* / Q000235:genetics*; D010641:Phenotype; D016601:RNA-Binding Proteins / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid
C433227:CNBP protein, human; D016601:RNA-Binding Proteins