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Pearson syndrome
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
A syndrome was first described in 1979 by Pearson and colleagues [1] in which four unrelated patients had refractory sideroblastic anemia with variable neutropenia and thrombocytopenia, and clinical and pathologic evidence of pancreatic dysfunction. One of these patients later developed Kearns–Sayre syndrome [2]. In 1991, study of this patient by McShane and colleagues [3] revealed a 4.9-kb deletion in mitochondrial DNA. This 4977-bp deletion was located between nt 8488 and nt 13,460. This deletion was also that most commonly observed in patients with Kearns–Sayre syndrome. The same deletion (Figure 55.1) had been reported in 1988 by Rotig and colleagues in an infant with Pearson syndrome [4]. Rotig and colleagues [5] have since studied a larger series of nine patients with Pearson syndrome, including one of Pearson's original patients; five had the previously identified 4.9-kb deletion, and four had distinctly different deletions in the same area of the genome. A consistent feature was the occurrence of direct repeats at the boundaries of the deletions [6], providing a possible mechanism for recombinations. Rotig and her colleagues [7] have since found a patient in whom there was an insertion, as well as a deletion in the mitochondrial DNA. In all patients studied, there was heteroplasmy of normal and deleted mitochondrial genomes.
Ophthalmology
Published in Shibley Rahman, Avinash Sharma, A Complete MRCP(UK) Parts 1 and 2 Written Examination Revision Guide, 2018
Shibley Rahman, Avinash Sharma
Kearns-Sayre syndrome is a mitochondrial inherited disease, and as such is only passed on by mothers to offspring. Red ragged fibres found in mitochrondrial cytopathy are found in Kearns-Sayre syndrome; mitochondrial myopathy, lactic acidosis and stroke-like episodes (MELAS); and Leber’s optic atrophy.
Mitochondrial and peroxisomal disorders
Published in Steve Hannigan, Inherited Metabolic Diseases: A Guide to 100 Conditions, 2018
Kearns-Sayre syndrome is a rare neuromuscuclar disorder that belongs to a group of rare disorders known as the mitochondrial encephalomyopathies. These disorders are characterised by a defect in the genetic material of the mitochondria (the cell structures that release energy), which impairs the functioning of the muscles and the brain. In many cases, tests reveal a deletion involving the mitochondrial DNA. In some cases Kearns-Sayre syndrome may be associated with other disorders or conditions.
Retinoschisis associated with Kearns-Sayre syndrome
Published in Ophthalmic Genetics, 2020
Julia Chertkof, Robert B. Hufnagel, Delphine Blain, Andrea L. Gropman, Brian P. Brooks
Kearns-Sayre Syndrome (KSS) is a rare mitochondrial myopathy classically characterized by external ophthalmoplegia, retinitis pigmentosa, and cardiomyopathy/cardiac conduction defects (1,2). Patients usually present before twenty years of age and can exhibit additional signs/symptoms, including: ptosis, cerebellar ataxia, Pearson’s syndrome (sideroblastic anemia, exocrine pancreas dysfunction, diabetes mellitus) (3), auditory/vestibular dysfunction (4), elevated cerebrospinal fluid protein, and chronic diarrhea with villous atrophy (5). KSS is most often due to mitochondrial genome rearrangements, including deletions and/or insertions (3,6,7). Here, we briefly report on a now 24-year-old male with molecularly confirmed KSS and a typical clinical presentation that was accompanied by retinoschisis incidentally discovered on optic coherence tomography.
Albinism and a mitochondrial DNA deletion
Published in Ophthalmic Genetics, 2020
Corina M Chilibeck, Emma E Glamuzina, Casey Y-J Ung, Emma L Blakely, Robert W Taylor, Andrea L Vincent
This patient initially presented with mild multi-system disease and few biochemical signatures of mitochondrial disease; however, it is well established that mtDNA rearrangement disorders, including single, large-scale mtDNA deletions, exhibit a wide spectrum of clinical presentations, particularly early in life (5,6). Due to the progressive nature of mitochondrial diseases, it is likely that she will develop a more severe Kearns–Sayre syndrome phenotype (6), prompting lifetime clinical surveillance and annual monitoring for multi-system disease. The 7,436bp mtDNA deletion has been reported in cardiac muscle in patients with mitochondrial cardiomyopathy (4), and accounted for ~10% of deleted mtDNA molecules in hippocampal tissue of patients with hippocampal sclerosis and drug-refractory temporal lobe epilepsy (7), although no ocular or other systemic features were described.
Scleral contact lenses for the management of complicated ptosis
Published in Orbit, 2018
Konstantinos Katsoulos, Gerasimos Livir Rallatos, Ioannis Mavrikakis
A 10-year-old female patient presented with the typical ophthalmological features of the Kearns–Sayre syndrome. She had severe myasthenic ptosis, severe ocular motility restriction in all gazes, and salt and pepper retinopathy OU. Best-corrected visual acuity (BCVA) was 6/24 OD and OS. Ptosis was more severe on the left eye, almost covering the whole pupil (Figure 4A). Her eyelid measurements were as follows: palpebral aperture OD: 5 mm and OS: 4 mm, MRD1 OD: 0.5 mm and OS 0 mm. Ptosis surgery in such cases is challenging and requires the frontalis suspension technique. Before proceeding with surgery, a scleral lens trial was offered (Epsilon V3 lenses, 16.5 mm diameter, Eyeart Laboratories). A pair of high-vault scleral lenses, in the order of 5000 μm, were chosen and fitted, in order to test the hypothesis of eyelid elevation. They indeed provided some upper eyelid support and widened slightly the palpebral aperture (Figure 4B). Inevitably, this technique resulted in a vault significantly larger than 100–200 μm, which was actually in the region of some millimeters. BCVA was still 6/24 OD and OS due to the underlying retinopathy, but the patient reported subjectively better vision, as the lens lifted the eyelid, uncovered the pupil, and allowed more light to enter the eye. Her eyelid measurements with the lenses worn were as follows: palpebral aperture OD: 6 mm and OS: 5 mm, MRD1 OD: 1.5 mm and OS 1 mm. The result, however, was evaluated as unsatisfactory by the medical team, and a second trial of “shelf” scleral lenses was proposed. The patient and her parents rejected this option due to handling difficulties with contact lenses, and opted for ptosis surgery.