Question: What is (are) Myoclonic epilepsy with ragged red fibers ?
Answer: Myoclonic epilepsy with ragged red fibers (MERRF) is a multisystem disorder characterized by myoclonus, which is often the first symptom, followed by generalized epilepsy, ataxia, weakness, and dementia. Symptoms usually first appear in childhood or adolescence after normal early development. The features of MERRF vary widely from individual to individual, even within families. Other common findings include hearing loss, short stature, optic atrophy, and cardiomyopathy with Wolff-Parkinson-White (WPW) syndrome. The diagnosis is based on clinical features and a muscle biopsy finding of ragged red fibers (RRF). In over 80% of cases, MERRF is caused by mutations in the mitochondrial gene called MT-TK. Several other mitochondrial genes have also been reported to cause MERRF, but many of the individuals with mutations in these other genes have additional signs and symptoms. Seizures associated with MERRF are generally treated with conventional anticonvulsant therapy. Coenzyme Q10 and L-carnitine are often used with the hope of improving mitochondrial function.
Source: GARD

Question: Is Myoclonic epilepsy with ragged red fibers inherited ?
Answer: Is myoclonic epilepsy associated with ragged red fibers genetic? If so, how is it inherited? MERRF is caused by mutations in the mitochondrial DNA and is transmitted by maternal inheritance. It is called maternal inheritance because a child inherits the great majority of their mitochondria from their mother through the egg. The Centre for Genetics Education provides a detail description of maternal inheritance. The mother of an individual with MERRF usually has a mitochondrial mutation and may or may not have symptoms. Or, an individual with MERRF may have a mitochondrial mutation that just occurred in them, called a de novo mutation. If the mother has the mitochondrial mutation, all of her children will inherit the mutation and may or may not have symptoms. All of her daughters children will also inherit the mitochondrial mutation. Her son's children are not at risk of inheriting the mutation.
Source: GARD