Intron associated with myotonic dystrophy type 2 and methods of use

A method for detecting a polynucleotide comprising a repeat tract within an intron 1 of a ZNF9 genomic sequence, the method comprising:

• digesting genomic DNA with a restriction endonuclease to obtain polynucleotides;
• probing the polynucleotides under hybridizing conditions with a detectably labeled probe which hybridizes to a polynucleotide containing a repeat tract within an intron 1 of a ZNF9 genomic sequence;
• and
• detecting the probe which has hybridized to the polynucleotides.

A method for identifying an individual not at risk for developing DM2, the method comprising:

• amplifying nucleotides of intron 1 regions of ZNF9 genomic sequences of an individual to form amplified polynucleotides, wherein the amplified polynucleotides comprise repeat tracts;
• comparing the size of the amplified polynucleotides;
• and
• analyzing the amplified polynucleotides for two not at risk alleles wherein an individual comprising two not at risk alleles is not at risk for developing DM2.

A method for identifying an individual that has DM2 or is at risk for developing DM2, the method comprising:

• digesting genomic DNA of an individual with a restriction endonuclease to obtain polynucleotides;
• probing the polynucleotides under hybridizing conditions with a detectably labeled probe that hybridizes to a polynucleotide containing a repeat tract within an intron 1 of a ZNF9 genomic sequence;
• detecting the probe that has hybridized to the polynucleotide;
• and
• analyzing the intron 1 region of the hybridized polynucleotide for one at risk allele comprising a repeat tract comprising at least about 75 CCTG repeats, wherein an individual comprising one allele comprising a repeat tract of at least about 75 CCTG repeats has DM2 or is at risk for developing DM2.

A method for identifying an individual that has DM2 or is at risk for developing DM2, the method comprising:

• providing a tissue sample from an individual;
• probing the tissue sample under hybridizing conditions with a detectably labeled probe which hybridizes to a polynucleotide containing a repeat tract within an intron 1 of a ZNF9 genomic sequence;
• detecting the probe which has hybridized to polynucleotides present in the tissue sample;
• and
• observing nuclei of cells present in the tissue sample, wherein the presence of the detectably labeled probe in nuclei of the cells indicates the individual has or is at risk for developing DM2.

A method for identifying an individual that is not at risk for developing DM2, the method comprising:

• providing a tissue sample from an individual;
• probing the tissue sample under hybridizing conditions with a detectably labeled probe which hybridizes to a polynucleotide containing a repeat tract within an intron 1 of a ZNF9 genomic sequence;
• detecting the probe which has hybridized to polynucleotides present in the tissue sample;
• and
• observing nuclei of cells present in the tissue sample, wherein the absence of the detectably labeled probe in nuclei of the cells indicates the individual is not at risk for developing DM2.