Application of whole exome sequencing in the diagnosis of Danon disease: annex 1 pedigree report

Abstract

Objective Using whole exome sequencing (WES) to help to make a definite diagnosis for confusing cases at clinical practice. Methods A 29-year old proband with clinical manifestations of mild myocardial hypertrophy and skeletal myopathy, muscle biopsy suggested multiple minimal axonal disease. WES was applied to find the possible pathogenic gene mutations and verified in the proband and her relatives with Sanger sequencing. Results A likely pathogenic heterogeneous variant LAMP2 c.974delT (p. Leu325fs) located on the X chromosome was detected in the proband, and LAMP2 encodes a type Ⅱ lysosome-associated membrane protein associated with Danon disease. Her younger brother with similar echocardiographic and muscle biopsy results also carried this hemizygous variant, but other healthy relatives including her father was negative for this variant. Therefore, there is a co-segregation of this variant with the disease in this family. Conclusions For those confusing cases which can′t be accurately diagnosed according to clinical manifestations and routine examination results, WES may be a more feasible and effective method for the differential diagnosis. Key words: Danon disease; LAMP2 gene; Whole exome sequencing