POLG1 mutations and stroke like episodes: a distinct clinical entity rather than an atypical MELAS syndrome
1 Neurological Unit, Ospedale di Desio, Azienda Ospedaliera di Desio e Vimercate, Monza, Italy
2 Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca’ Granda Ospedale Maggiore Policlinico, Milan, 20122, Italy
3 Neuromuscular Unit, IRCCS Foundation Ca’ Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, University of Milan, Milan, 20122, Italy
4 Cerebrovascular Unit, IRCCS Foundation Neurological Institute ‘C.Besta’, Via Celoria 23, 20135, Milan, Italy
BMC Neurology 2013, 13:8 doi:10.1186/1471-2377-13-8Published: 15 January 2013
POLG1 mutations have been associated with MELAS-like phenotypes. However given several clinical differences it is unknown whether POLG1 mutations are possible causes of MELAS or give raise to a distinct clinical and genetic entity, named POLG1-associated encephalopathy.
We describe a 74 years old man carrying POLG1 mutations presenting with strokes, myopathy and ragged red fibers with some atypical aspects for MELAS such as late onset, lack of cerebral calcification and presence of frontal and occipital MRI lesions better consistent with the POLG associated-encephalopathy spectrum.
The lack of available data hampers a definite diagnosis in our patient as well as makes it difficult to compare MELAS, which is a clearly defined clinical syndrome, with POLG1-associated encephalopathy, which is so far a purely molecularly defined syndrome with a quite heterogeneous clinical picture. However, the present report contributes to expand the phenotypic spectrum of POLG1 mutations underlining the importance of searching POLG1 mutations in patients with mitochondrial signs and MELAS like phenotypes but negative for common mtDNA mutations.