Elaboration of genotype phenotype correlation in families with dystrophinopathy

Duchenne muscular dystrophy (DMD; OMIM#310200) and Becker muscular dystrophy (BMD; OMIM #300376) are X linked allelic muscle diseases caused by the mutations in dystrophin gene. Additionally, intellectual disability is seen approximately in one third of DMD patients. Also there are some researches revealing some neurodevelopmental disorders like attention deficiency and hyperactivity disorder (ADHD) are more common in these patients compared to the population. We aim to exhibit genotypic features of the patients with dystrophinopathy with genetic diagnose performed in our laboratory; examine the correlation between their genotypes and phenotypes and compare our findings with literature. All cases in which genetic diagnosis were performed between January 2007 and July 2018 were included in the study, and the clinical and genetic test data of the cases were obtained by scanning the file and medical record system of the Department of Pediatric Neurology in addition to the Department of Medical Genetics. Besides, IQ values of the 29 patients from our follow-up cases volunteer to join in our study were measured and their psychiatric evaluation was made. We shared the data of 347 patients with D/BMD. We detected 293 deletions, 41 duplications including one or more exons. Our deletion rate was 87.7% and duplication rate was consistent with 12.3%. We found point mutations in 13 cases and 6 of them were novel mutations. The 93.9% (138/147) of DMD patients were consistent with the reading frame rule, whereas this rate was 89.7% for BMD patients. Intellectual disability and ADHD were determined to accompany to DMD patients in 24.1% and 26.3%, respectively. This is the largest study examining the MLPA based genotype data in Turkish D/BMD patients. Studies showing the relationship between genotype and phenotype provide precious data for both clinical and basic sciences. In this sense, our study will contribute to the literature on the mechanisms of dystrophinopathies. Key Words: DMD gene, Duchenne muscular dystrophy, MLPA, Turkish population