Autosomal dominant Kearns-Sayre syndrome

Kearns-Sayre Syndrome: A Case Report and Review

In 1958, Kearns and Sayre described a multisystem entity, now known as Kearns-Sayre syndrome (KSS). The syndrome is defined as exhibiting a triad of thus far unexplained degenerative conditions: progressive external ophthalmoplegia, retinal pigmentary degeneration, and heart block. Commonly accompanying findings include cerebellar dysfunction and CSF protein levels above 100 mg/dl. Symptoms usually appear in early childhood, but the onset has been seen occasionally in young adults. KSS is a mitochondrial disorder that occurs rarely; the actual incidence is unknown. Ocular findings consist of bilateral ptosis, chronic progressive external ophthalmoplegia, and pigmentary retinopathy. Corneal clouding and optic neuritis are infrequent.

We herein report a classic case of Kearns Sayre syndrome and discuss the findings.

Bilateral lid/brow elevation procedure for severe ptosis in Kearns-Sayre syndrome, a mitochondrial cytopathy

Background

The purpose of this work was to determine the effectiveness and possible complications encountered with bilateral fascia lata lid suspension used to correct blepharoptosis in patients with Kearns-Sayre syndrome.

Methods

This was a retrospective study of seven patients with Kearns-Sayre syndrome who had a minimum of 1 year of follow-up. A bilateral fascia lata sling was used to correct the ptosis. Preoperative and postoperative measurements of the vertical lid fissure width (VFW) and marginal reflex distance (MRD) were performed. The Student’s t-test was used to analyze the results.

Results

The mean preoperative VFW and MRD measurements were 4±2.45 mm and 0.14±0.92 mm, respectively. The mean postoperative VFW and MRD measurements were 7.71±1.85 mm, and 2.86±1.69 mm, respectively. All preoperative and postoperative values were considered to be statistically significant (P<0.01). Adequate elevation of the lids was obtained in all patients, both functionally and aesthetically. All of the patients showed a mild symmetric postoperative inferior version lagophthalmos, and one patient developed corneal ulceration and scarring due to corneal exposure and a weak Bell’s phenomenon.

Conclusion

The surgical technique described to correct the blepharoptosis found in patients with Kearns-Sayre syndrome was found to be efficient and relatively safe. The correction should be conservative to decrease the risk of postoperative corneal damage that occurred in one patient.

Age-related changes in the activities of respiratory chain complexes and mitochondrial morphology in Drosophila

Using Drosophila melanogaster, we examined changes in the activities of some of the respiratory enzyme complexes with age. The age-related decreases of enzyme activities were observed especially in complex I. We also examined changes in the ultrastructure of mitochondria in the flight muscles of thoraces. The results indicated that the mitochondrial size varied more widely in aged flies than in young ones, in addition to the slight increase in the average size with age. These changes had already appeared before the survival began to decrease, clearly indicating that the accumulation of such changes seriously damages mitochondrial function.

Mitochondrial disorders with significant ophthalmic manifestations

Mitochondrial diseases are a clinically hetyerogenous group of disorders. They can be caused by mutations of nuclear or mitochondrial DNA (mtDNA). Some affect a single organ, but many involve multiple organ systems and often present with prominent neurologic and myopathic features. The eye is frequently affected, along with muscles and brain, but multisystem disease is common. Ophthalmic manifestations include cataract, retinopathy, optic atrophy, cortical visual loss, ptosis and ophthalmoplegia. Kearns-Sayre Syndrome (KSS), Mitochondrial Encephalopathy, Lactic Acidosis Stroke (MELAS), Myoclonic Epilepsy and Ragged Red Fiber myopathy (MERRF) and Lebers Hereditary Optic Neuropathy (LHON) are well known clinical entities that are secondary to mtDNA abnormalities, which has ophthalmic manifestations. Mitochondrial Dysfunction should be considered in the differential diagnosis of progressive multisystem disorder and specifically if there is associated neuro-ophthalmic manifestations, which may be the presenting symptom of these disorders.

Anticipation of autosomal dominant progressive external ophthalmoplegia with hypogonadism

A large Swedish family with members affected by progressive external ophthalmoplegia with hypogonadism were followed-up and reviewed. Hypogonadism included delayed sexual maturation, primary amenorrhea, early menopause, and testicular atrophy. Cataracts, cerebellar ataxia, neuropathy, hypoacusia, pes cavus, tremor, parkinsonism, depression, and mental retardation were other features observed in this family. Muscle biopsy samples of advanced cases showed ragged-red fibers, focal cytochrome c oxidase deficiency, and multiple mtDNA deletions by Southern blot analysis. An autosomal dominant mode of inheritance was evident with anticipation in successive generations. Linkage analysis excluded the chromosome 10q23.3-q24.3 region reported as being linked to the disease in a Finnish family with autosomal dominant progressive external ophthalmoplegia. We report for the first time clinical evidence for anticipation in a family with autosomal dominant progressive external ophthalmoplegia. We hypothesize that the nuclear gene causing this enigmatic disorder may be directly influenced by an expansion of an unstable DNA sequence and that the resulting phenotype is caused by a concerted action with multiple deletions of mtDNA.

Mitochondrial encephalomyopathy with autosomal dominant inheritance: a clinical and genetic entity of mitochondrial diseases

We report a Japanese family with chronic progressive external ophthalmoplegia (CPEO) with autosomal dominant inheritance, and review 54 reported CPEO patients in seven families (including the present family) with autosomal dominant inheritance and mtDNA deletions in the skeletal muscle. Mean age at onset in the CPEO was 26 years, which is older than that in published solitary cases. In addition to blepharoptosis and external opthalmoplegia, proximal muscle atrophy and weakness were found in 62%, hearing loss in 25%, and ataxia in 17% of the patients. Retinal degeneration was not found, and cardiac involvement was very rare. mtDNA deletions in the muscle were multiple and large scale, and all such deletions were located in the non-D-loop region. Autosomal dominant CPEO has unique clinical features which differ from those of solitary CPEO, and is associated with multiple large-scale mtDNA deletions. Thus, autosomal dominant CPEO can be considered a clinical and genetic entity of mitochondrial diseases.

Olivopontocerebellar atrophy with retinal degeneration. Fundus characteristics and diagnostic MRI findings

Olivopontocerebellar atrophy with retinal degeneration (OPCA type III) and autosomal dominant cerebellar atrophy of late onset (type II) appear to represent the same disease which is characterized by dominantly inherited cerebellar ataxia and pigmentary retinal degeneration. In June, 1988, a 15-year-old girl presented with objective visual acuity loss but no other findings. When seen again in January, 1991, macular changes were noted. At this time, her mother, diagnosed with multiple sclerosis, was examined and found to have atrophic macular lesions and poor vision. A brain MRI was performed which showed findings diagnostic of OPCA type III, including cerebellar and pontine atrophy and specific loss of the inferior olives. Fundus features, electroretinographic results and other clinical findings in OPCA type III are discussed and diagnostic MRI lesions are demonstrated.

Endocrine dysfunction in Kearns-Sayre syndrome

Kearns-Sayre syndrome (KSS) is a form of mitochondrial myopathy in which specific clinical features, namely progressive external ophthalmoplegia, pigmentary retinal degeneration and cardiac conduction defects, occur. KSS has also been associated with a variety of endocrine and metabolic disorders, in particular short stature, gonadal failure, diabetes mellitus, thyroid disease, hyperaldosteronism, hypomagnesaemia, and bone, tooth and calcification abnormalities. A case is described exhibiting all of these features. A survey of the literature was conducted to determine the prevalence of these conditions among reported cases. Cases with hypoparathyroidism were considered separately to see if they constituted a distinct subgroup with multiple endocrine dysfunction. Short stature was common, being documented in 38% of cases. Gonadal dysfunction before or after puberty was also common (20% of cases) and affected both sexes equally. Diabetes mellitus was recorded in 13% of cases, half of which required insulin. Thyroid disease, hyperaldosteronism and hypomagnesaemia were uncommon but were probably not looked for in many cases. Bone or tooth abnormalities and calcification of the basal ganglia were found both in those with and without hypoparathyroidism. While endocrine and metabolic dysfunction was found more commonly in those with hypoparathyroidism this is likely to be due to increased recognition rather than increased prevalence. No evidence of an autoimmune polyendocrine syndrome including hypoparathyroidism was found.

Variation in retinal changes and muscle pathology in mitochondriopathies

A variety of retinal changes that have so far not been classified under mitochondriopathies can now be included in this group, since muscle biopsy has identified ragged-red fibers with pathological mitochondriae. The ophthalmological findings in our relatively large group of 12 patients with mitochondrial myopathies are compared with the spectrum of myopathic findings. No obvious correlation exists between the severity of the pathological retinal changes and the characteristic of the myopathic alterations. In addition to fine pigmentation and depigmentation, severe dystrophic changes of the retina, pigment epithelium, and the choroid were observed. In two patients with severe chorioretinal dystrophy the correlation with generalized mitochondriopathy was not suspected prior to muscle biopsy.

A dominantly inherited progressive disease in a black family characterised by cerebellar and retinal degeneration, external ophthalmoplegia and abnormal mitochondria

A report is given of a black family with a dominantly inherited, neuro-retinal degeneration associated with abnormally large mitochondria, in which the cristae are disoriented. The disease is characterised by progressive external ophthalmoplegia, clear-cut macular degeneration, cerebellar dysarthria, spastic paraplegia and finally facial and bulbar weakness. A similar illness has been described in black families and individuals and we suggest that the disease may represent a specific syndrome, possibly confined to blacks, that lies within the spectrum of the so-called mitochondrionopathies.

Nemaline myopathy associated with hypertrophic cardiomyopathy

Nemaline myopathy is not usually considered to involve cardiac muscle and rarely is associated with nocturnal hypoventilation. We report a boy, 5 1/2 years of age, with nemaline myopathy who presented with respiratory failure. Echocardiography demonstrated the septum to left ventricular posterior wall ratio to be increased which is consistent with a hypertrophic cardiomyopathy. Because of nocturnal hypoventilation, tracheostomy was placed for ventilatory assistance. A process involving both muscle and nervous tissue may underlie this congenital myopathy; routine cardiac and pulmonary function evaluations may be indicated in these patients.

Mitochondrial myopathy: a genetic study of 71 cases

Of 71 index cases with histologically defined mitochondrial myopathy, 13 (18%) had relatives who were definitely affected with a similar disorder. Eight familial cases from four families were confined to a single generation. In five families maternal transmission to offspring occurred. There were no instances of paternal transmission, but one patient had an affected cousin in the paternal line. No consistent clinical syndrome or pattern of inheritance emerged for any identified defect of the mitochondrial respiratory chain, localised biochemically in 41 cases. Overall, the recurrence rate was 3% for sibs and 5.5% for offspring of index cases. Review of published reports of familial cases of mitochondrial myopathy suggests that the ratio of maternal to paternal transmission is about 9:1. We conclude that these disorders may be caused by mutations of either nuclear or mitochondrial genes.

Chronic progressive external ophthalmoplegia. II. A qualitative and quantitative electronmicroscopy study of skeletal muscles

This study quantifies the major electron microscopic changes in limb muscle biopsies from 31 out of 34 patients with the syndrome of chronic progressive external ophthalmoplegia. Patients were divided into three clinical groups -- A) 10 sporadic cases with muscle weakness only; B) 9 familial cases with muscle weakness only; C) 15 cases with muscle weakness and one or more of the following features: pigmentary retinopathy, cerebellar ataxia, pyramidal signs and peripheral neuropathy. Electron microscopic mitochondrial abnormalities were found in all groups (8 patients from group A, 3 from group B, 14 from group C). Quantitative measurements of certain muscle fibre constituents, using a point-counting technique, revealed decreased myofibril volume-fractions and increased volume-fractions of mitochondria, glycogen and lipid in some biopsies from each group. Mitochondrial volume-fractions correlated positively with lipid content, the proportion of type 1 fibres, and the percentage of fibres with increased oxidative enzyme activity. The three groups defined clinically showed no significant differences in terms of the relative proportions of these measured constituents.

Transient postictal cortical blindness

An 8-year-old boy with insulin-dependent diabetes mellitus and a seizure disorder demonstrated transient visual loss after severe seizure activity. The role of hypoglycemia in relation to his transient cortical blindness remains indeterminate. The nature of the cortical involvement, the rate of visual recovery, and prior reports of postictal phenomena emphasize the relatively benign nature of this condition in children.

Histopathology of mitochondrial cytopathy and the Laurence-Moon-Biedl syndrome

Clinical and histopathological studies of two patients with distinctly different inherited juvenile retinal dystrophies indicate that the ocular defect in mitochondrial cytopathy involves the underlying pigment epithelium, whereas in the Laurence-Moon-Biedl syndrome the photoreceptor cells are primarily affected.

Dominant optic atrophy, deafness, ptosis, ophthalmoplegia, dystaxia, and myopathy. A new syndrome

Twenty-three members of a 96-member family exhibited an autosomal dominant disorder which has not previously been described. This disorder involves progressive optic atrophy, abnormal electroretinography without retinal pigment changes, and progressive sensorineural hearing loss usually evident in the first or second decade of life. In midlife, ptosis, ophthalmoplegia, dystaxia, and a nonspecific myopathy occur.

Near-fatal Kearns-Sayre syndrome. A case report and review of clinical manifestations

The Kearns-Sayre syndrome is a relatively uncommon condition which occurs in childhood and is characterized by neurologic dysfunction and abnormalities in atrioventricular (AV) conduction. The high mortality rate is directly attributable to the cardiovascular manifestations of this syndrome. We report a case, with documentation of a "near-fatal" episode, and review the pertinent clinical features of the syndrome.

Mitochondrial inheritance in a mitochondrially mediated disease

Mendelian inheritance involves the transmission to successive generations of DNA contained in genes in the nucleus, but DNA is also contained in mitochondria, where it is believed to be responsible for the encoding of certain mitochondrial enzymes. Since nearly all mitochondrial DNA is maternally transmitted, one might expect a nonmendelian pattern of inheritance in mitochondrial cytopathy, a syndrome in which there are abnormalities in mitochondrial structure and deficiencies in a variety of mitochondrial enzymes. We studied the pedigrees of 6 affected families whose members we had examined personally and of 24 families described in the literature. In 27 families, exclusively maternal transmission occurred; in 3 there was also paternal transmission in one generation. Altogether, 51 mothers but only 3 fathers had transmitted the condition. These results are consistent with mitochondrial transmission of mitochondrial cytopathy; the inheritance and enzyme defects of mitochondrial cytopathy can be considered in the light of recent evidence that subunits of respiratory-enzyme complexes are encoded solely by mitochondrial DNA. The occasional paternal transmission may be explained if certain enzyme subunits that are encoded by nuclear DNA are affected.

The atypical pigmentary retinopathy of Kearns-Sayre syndrome. A light and electron microscopic study

Two postmortem eyes from a 52-year-old man with Kearns-Sayre syndrome were examined by light, scanning, and transmission electron microscopy. Prior to death, pronounced ptosis, total external ophthalmoplegia, an episodic ventricular cardiac arrhythmia, and an atypical pigmentary retinopathy characterized by "choroidal sclerosis" and pigment clumping were documented. Histopathologic examination revealed atrophy of the retinal pigment epithelium and outer retina that was most marked posteriorly. The preservation of photoreceptors appeared to mirror the health of the underlying retinal pigment epithelium. Numerous healthy appearing rods were present in the relatively well-preserved temporal retina. The pattern of photoreceptor degeneration observed in this form of "atypical retinitis pigmentosa" suggests that the primary defect may reside in the retinal pigment epithelium.

Hypertrophic cardiomyopathy is a component of subacute necrotizing encephalomyelopathy

Twelve patients, ranging from the neonatal period through adolescence, with subacute necrotizing encephalomyelopathy (Leigh disease) were studied. Autopsies of these patients demonstrated an associated hypertrophic cardiomyopathy in seven; of these, four had asymmetric septal hypertrophy. In two patients, the cardiac lesion was observed by premortem echocardiograms. The common occurrence of a cardiac lesion emphasizes the probable systemic nature of SNEM and may serve to segregate these patients into two groups. Because of the involvement of the two systems, we suggest that SNEM may have some relation to a variety of other cardioneurologic syndromes.

Kearns syndrome: a heterogeneous group of disorders with CPEO, or a nosological entity?

In connection with 4 new cases of Kearns syndrome (multisystem form of mitochondrial CPEO), the condition was found to be present in slight to oligosymptomatic form in all 4 families. The marker symptom in subclinical patients was nearly always ptosis (sometimes very slight) and occasionally diabetes. In the literature other endocrine disorders, retinal anomalies, deafness, growth disturbances, etc., have been noted as subclinical symptoms in former generations. Heredity appears to be autosomal dominant in these 4 families, with very variable expressivity. The possibility that one gene is responsible for the disease seems to be plausible, but the marked variation in expressivity suggests a modifying influence of other alleles; in this sense, therefore, one may speak of multifactor inheritance. Supporting facts could also be found in the literature, where there was autosomal dominant heredity of the disease-carrying gene, but for its complete expression 'amplifying' factors (alleles) were needed. The pleiotropia of the disease-carrying gene is explained by a mitochondrial disorder of various organs. On the basis of the heredity, therefore, Kearns syndrome is not a syndrome but a disease. The most serious, most progressive and most extensive (multisystem) variant of Kearns disease is the infantile form, known as the 'Kearns-Sayre syndrome. When the expressivity of the disease is less extensive it usually occurs later in life and is less progressive: the adult form of Kearns disease.

Ophthalmoplegia-plus

The occurrence of chronic progressive external ophthalmoplegia, pigmentary retinal dystrophy and cardiac disturbances associated with arachnodactily, sternal deformity, high arched palate and severe myopia is reported. A pedigree analysis of this Jewish-Iranian family strongly suggests that the condition is inherited as autosomal recessive trait. The terminology of the condition and the spectrum of it variable phenotypic expression is described.