Höfundar:
Haukur Svansson, Erla Guðbjörg Hallgrímsdóttir, Hildur Ólafsdóttir, Ólafur Árni Sveinsson, Vigdís Fjóla Stefansdóttir, Eiríkur Bríem, Sigurlaug Sveinbjörnsdóttir, Jón Jóhannes Jónsson
Background/Objectives: Myotonic Dystrophy type 1 (DM1) is a multisystemic disease. Inheritance is autosomal dominant with anticipation due to increased number of CTG tandem repeats in the DMPK gene. The prevalence of DM1 differs between countries, with an average general world estimate of 12,5 per 100.000.1 We previously documented in 2005 a high prevalence of DM1 (28,2 per 100.000).2 The current study reexamined the prevalence and diagnosis.
Methods: Data from Landspitali University Hospital, Akureyri Hospital, Medical Director of Health and independent clinics were accessed. Five ICD-9 and seven ICD-10 relevant numbers were searched for. Additionally, results of DMPK genetic testing were obtained from Landspítali. Inclusion criteria were Icelandic residency, alive on January 1, 2021 and any of the following: Clinical diagnosis of DM1, positive DMPK genetic test or positive EMG test.
Results: In Iceland, 178 individuals had been diagnosed with DM1, of which 136 were alive, giving a point prevalence of 37 per 100.000. In 111 cases the reason leading to diagnosis was documented. Most cases (77%) were diagnosed with indirect family-mediated cascade testing and 23% due to symptoms.
Conclusion: Thorough ascertainment of diagnosed cases found the prevalence of DM1 in Iceland to be three times the world average. Our data demonstrates the importance of cascade testing in this disease.
References:
1. Harper (2001) Myotonic Dystrophy. 2. Leifsdóttir et al. (2005) Prevalence of myotonic dystrophyin
Iceland. Icelandic Med J.
Grants: The Icelandic Student Innovation Fund and Myotonic Dystrophy Association of Iceland.