All of the following statements about inheritance of Myotonic Dystrophy are true, except:
The gene for Type-1 Myotonic Dystrophy (DMPK) is located on the long arm of chromosome 19. The gene Type 2 Myotonic Dystrophy (CNBP) located on the long arm of chromosome 3. Myotonic Dystrophy: These two types of Myotonic Dystrophy that are caused by different genes both of which are inherited as Autosomal Dominant disorders. Myotonic Dystrophy Type 1: Type 1 is caused by a mutation in the DMPK gene. DMPK stands for Dystrophica Myotonica-protein kinase gene. Most frequently a CTG trinucleotide repeat in the untranslated DMPK gene has been identified to be responsible for Type 1 Disease. The gene is located on the long arm of chromosome 19. Myotonic Dystrophy Type 2: Type 2 is caused by a mutation in the CNBP gene. CNBP stands for &;CCHC-type Zinc Finger Nucelic acid Binding Protein&; (CNBP/ZNF9) Most frequently, a CCTG tetra-nucleotide repeat within an intron of the CNBP (ZNF9) gene has been identified to be responsible for PROMM. The gene is located on the long arm of chromosome 3. Myotonic dystrophy type 2, Also known as Proximal myotonic myopathy (PROMM), is a milder disease that has mainly of the same features as Myotonic Dystrophy Type 1. Ref: Robbins and Cotran 9th edition vol 2
Type 1 is caused by mutation in DMPK gene
Type 2 is caused by mutation in CNBP gene
Type 2 gene is located on Chromosome 19
Type 1 is caused by a CTG trinucleotide repeat expansion
Musculoskeletal system