The Genotype-Phenotype Correlation in Children with Duchenne Muscular Dystrophy: Single Center Experience

Öz

Objective: Duchenne muscular dystrophy (DMD) is characterized by progressive muscle weakness caused by mutations in the dystrophin gene. In this study, we aimed to investigate the relationship between different mutations in the dystrophin gene and motor functions in children with DMD.

Material and Methods: Children with DMD followed-up between January 2016 and January 2018 were evaluated. Demographic data, genetic mutations, duration of steroid treatment and 6-minute walk test results were recorded. The children were divided into three groups according to the mutation in the dystrophin gene as deletion, duplication and point mutation. The 6-minute walk test results were compared between the three groups.

Results: Thirty-three male patients with DMD at a mean age of 6.7 ± 2 years (4-11 years) were included in the study. Twenty-two patients (67%) had deletion, 6 patients (18%) had duplication and 5 patients (15%) had point mutations. The mean duration of steroid treatment was 1.6 ± 0.8 years (0.5 to 3 years) in 18 patients receiving steroid treatment. There were no significant differences between the three groups in terms of age and steroid use (p> 0.05). The mean 6-minute walk test result was 324 ± 51 meters (220-427 meters), 326 ± 77 meters (264-440 meters) and 285 ± 38 meters (250-326 meters) in children with deletion, duplication and point mutation of the dystrophin gene, respectively. Although the walking distance in 6-minute walk test was shorter in children with point mutation compared to the children with deletion and duplication, there was no statistically significant difference observed between the 3 groups (p> 0.05).

Conclusion: There is no significant relationship between the type of mutation in the dystrophin gene and clinical course in children with DMD. The progression rate of the DMD may show a difference.

Duchenne Musküler Distrofili Çocuklarda Genotip-Fenotip İlişkisi: Tek Merkez Deneyimi

Öz

Amaç: Duchenne musküler distrofi (DMD), DMD genindeki mutasyonların neden olduğu ilerleyici kas güçsüzlüğü ile seyreden bir hastalıktır. Bu çalışmada, DMD tanılı çocuklarda DMD genindeki farklı mutasyonlar ile motor fonksiyonlar arasındaki ilişkiyi incelemeyi amaçladık.

Yöntem: Ocak 2016 ile Ocak 2018 tarihleri arasında DMD tanısı ile takip edilen, yürüyebilen ve ek hastalığı olmayan çocuklar çalışmaya dahil edildi. Demografik veriler, genetik mutasyon sonuçları, steroid kullanım süreleri ve 6 dakika yürüme testi sonuçları kaydedildi. Çocuklar DMD genindeki mutasyona göre delesyon, duplikasyon ve nokta mutasyona sahip olanlar olarak 3 gruba ayrıldı. Üç grup arasında 6 dakika yürüme testi sonuçları karşılaştırıldı.

Bulgular: DMD tanılı 33 erkek hasta çalışmaya dahil edildi, ortalama yaşları 6,7 ± 2 yıldı (4-11 yıl). Yirmi iki hastada (%67) delesyon, 6 hastada (%18) duplikasyon, 5 hastada (%15) nokta mutasyon mevcuttu. Steroid tedavisi alan 18 hastanın ortalama steroid kullanma süresi 1,6 ± 0,8 yıldı (0,5-3 yıl). Üç grup arasında yaş ve steroid kullanım süreleri açısından anlamlı farklılık saptanmadı (p> 0,05). DMD geninde delesyon, duplikasyon ve nokta mutasyon saptananların ortalama 6 dakika yürüme mesafesi sırasıyla 324 ± 51 metre (220-427 metre), 326 ± 77 metre (264-440 metre) ve 285 ± 38 metreydi (250-326 metre). Altı dakika yürüme testi açısından nokta mutasyon saptanan hastalarda delesyon ve duplikasyon saptanan hastalara göre yürüme mesafesi daha kısa olmakla birlikte istatiksel olarak 3 grup arasında anlamlı farklılık saptanmadı (p> 0,05).

Sonuç: DMD tanılı çocuklarda DMD genindeki mutasyonun tipi ile klinik gidiş arasında anlamlı ilişki bulunmamaktadır. Hastalığın ilerleme hızı benzer mutasyon tiplerinde dahi bireysel farklılıklar gösterebilmektedir. 

Anahtar Kelimeler

• çocuk
• distrofi
• gen

Kaynakça

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