Kearns-Sayre syndrome: clinical and molecular diagnosis of the disease and treatment with recombinant GH (rGH) complicated by a severe cardiac conduction deficit and cardiomyopathy
M. Obara-Moszynska, J. Maceluch, W. Bobkowski, A. Baszko, O. Jaremba, M. Krawczynski & M. Niedziela
Introduction: Kearns-Sayre syndrome (KSS) is a rare mitochondrial cytopathy. The diagnosis of KSS is made on the classical triad of symptoms: onset of the disease <20 years of age, progressive external ophthalmoplegia (PEO) and pigmentary retinopathy (PR). KSS is manifested also by other systemic abnormalities: cardiac conduction defects, different neurological abnormalities and several endocrine disorders. A variety of deletions and/or duplications in mtDNA, affecting genes encoding respiratory chain proteins, are found in most cases. The mutated mtDNA coexists with normal molecules (heteroplasmy) and the proportion of mutated to normal mtDNA correlates with the severity of clinical symptoms.
Case report: The adopted boy was born small for gestational age at term. From the 2nd year of life chronic PEO was observed. Additionally the PR was observed. From early childhood he presented short stature. In the age of 11 years, in the EMG the myogenic pattern was revealed and KSS was diagnosed. MRI of the head showed hypoplasia of pituitary gland. Long-range PCR analysis disclosed a 7663 bp long deletion in mtDNA in 634014 003 nucleotide region. In the age of 12 years GH deficiency was recognized and the rGH therapy was started. In the age of 15 years complete atrioventicular block was diagnosed. The patient was applied with pacemaker. During next 6 months progressive insufficiency of left ventricle was observed, the echo sound showed the features of dilated cardiomyopathy. The rGH treatment was finished with final height 163 cm.
Conclusions: The effect of rGH therapy in our patient was satisfactory even a big mtDNA deletion and severe cardiac disturbances occurred. Cardiac disturbances were a part of the syndrome, not related to rGH therapy. Based on the literature and the examined patient we state that growth of KSS patients, spontaneous or promoted with rGH, is unpredictable.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.