Jessica Fein’s daughter Dalia has the mitochondrial disease MERRF Syndrome. Jessica spoke with us at the Rare Disease Film Festival, an event showcasing a myriad of films from around the world that addresses the challenges of life with a rare disease.

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.

Because muscle cells and nerve cells have especially high energy needs, muscular and neurological problems are common features of diseases that affect the mitochondria. MERRF is a progressive multi-system syndrome with symptoms that begin during childhood, but onset may occur in adulthood. The rate of progression varies widely. Onset and extent of symptoms can differ widely from individual to individual and among affected siblings.

The classic features of MERRF include:
– Myoclonus (brief, sudden, twitching muscle spasms) – the most characteristic symptom
– Epileptic seizures
– Ataxia (impaired coordination)
– Ragged-red fibers (a characteristic microscopic abnormality observed in muscle biopsy of patients with MERRF and other mitochondrial disorders)

Additional symptoms may include: hearing loss, lactic acidosis (elevated lactic acid level in the blood), short stature, exercise intolerance, dementia, cardiac defects, eye abnormalities, and speech impairment.