Danon disease is a genetic X-linked dominant disorder. The disease is linked to genetic defects in the lysosome-associated membrane protein 2 (LAMP2) gene, encoding the LAMP2 protein. The mutation leads to dysfunction of the muscle cells. The disease manifests itself in the form of cardiomyopathy, myopathy and mental disorders.

The patient has a mutation of the LAMP2 gene in exon 7 c.889_891del, resulting in a deletion of the amino acid p.Lys297del.