[Clinical characteristics of Danon disease].

Objective: To review the clinical data of 7 patients with Danon disease and analyze their clinical characteristics. Methods: The medical records of 7 patients with Danon disease, who were hospitalized in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from April 2008 to July 2021, were reviewed and summarized, of which 6 cases were diagnosed as Danon disease by lysosomal-associated membrane protein-2 (LAMP-2) gene mutation detection and 1 case was diagnosed by clinicopathological features. Clinical manifestations, biochemical indexes, electrocardiogram, echocardiography, skeletal muscle and myocardial biopsy and gene detection results were analyzed, and patients received clinical follow-up after discharge. Results: Six patients were male and average age was (15.4±3.5) years and the average follow-up time was (27.7±17.0) months. The main clinical manifestations were myocardial hypertrophy (6/7), decreased myodynamia (2/7) and poor academic performance (3/7). Electrocardiogram features included pre-excitation syndrome (6/7) and left ventricular hypertrophy (7/7). Echocardiography examination evidenced myocardial hypertrophy (6/7), and left ventricular dilatation and systolic dysfunction during the disease course (1/7). The results of skeletal muscle biopsy in 6 patients were consistent with autophagy vacuolar myopathy. Subendocardial myocardial biopsy was performed in 3 patients, and a large amount of glycogen deposition with autophagosome formation was found in cardiomyocytes. LAMP-2 gene was detected in 6 patients, and missense mutations were found in all these patients. During the follow-up period, implantable cardioverter defibrillator implantation was performed in 1 patient because of high atrioventricular block 4 years after diagnosis, and there was no death or hospitalization for cardiovascular events in the other patients. Conclusion: The main clinical manifestations of Danon disease are cardiomyopathy, myopathy and mental retardation. Pre-excitation syndrome is a common electrocardiographic manifestation. Autophagy vacuoles can be seen in skeletal muscle and myocardial pathological biopsies. LAMP-2 gene mutation analysis is helpful in the diagnose of this disease.

Clinical characteristics of Danon disease / 中华心血管病杂志

Objective: To review the clinical data of 7 patients with Danon disease and analyze their clinical characteristics. Methods: The medical records of 7 patients with Danon disease, who were hospitalized in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from April 2008 to July 2021, were reviewed and summarized, of which 6 cases were diagnosed as Danon disease by lysosomal-associated membrane protein-2 (LAMP-2) gene mutation detection and 1 case was diagnosed by clinicopathological features. Clinical manifestations, biochemical indexes, electrocardiogram, echocardiography, skeletal muscle and myocardial biopsy and gene detection results were analyzed, and patients received clinical follow-up after discharge. Results: Six patients were male and average age was (15.4±3.5) years and the average follow-up time was (27.7±17.0) months. The main clinical manifestations were myocardial hypertrophy (6/7), decreased myodynamia (2/7) and poor academic performance (3/7). Electrocardiogram features included pre-excitation syndrome (6/7) and left ventricular hypertrophy (7/7). Echocardiography examination evidenced myocardial hypertrophy (6/7), and left ventricular dilatation and systolic dysfunction during the disease course (1/7). The results of skeletal muscle biopsy in 6 patients were consistent with autophagy vacuolar myopathy. Subendocardial myocardial biopsy was performed in 3 patients, and a large amount of glycogen deposition with autophagosome formation was found in cardiomyocytes. LAMP-2 gene was detected in 6 patients, and missense mutations were found in all these patients. During the follow-up period, implantable cardioverter defibrillator implantation was performed in 1 patient because of high atrioventricular block 4 years after diagnosis, and there was no death or hospitalization for cardiovascular events in the other patients. Conclusion: The main clinical manifestations of Danon disease are cardiomyopathy, myopathy and mental retardation. Pre-excitation syndrome is a common electrocardiographic manifestation. Autophagy vacuoles can be seen in skeletal muscle and myocardial pathological biopsies. LAMP-2 gene mutation analysis is helpful in the diagnose of this disease.

Mutations of the gene FNIP1 associated with a syndromic autosomal recessive immunodeficiency with cardiomyopathy and pre-excitation syndrome.

AMPK (adenosine monophosphate-activated protein kinase) is phosphorylated (AMPK-P) in response to low energy through allosteric activation by Adenosine mono- or diphosphate (AMP/ADP). Folliculin (FLCN) and the FLCN-interacting proteins 1 and 2 (FNIP1, 2) modulate AMPK. FNIP1 deficiency patients have a AMPK-P gain of function phenotype with hypertrophic cardiomyopathy, Wolff-Parkinson-White pre-excitation syndrome, myopathy of skeletal muscles and combined immunodeficiency.

Perioperative management of patients with genetic multisystem diseases associated with pre­excitation.

Pre-excitation is associated with life-threatening arrhythmias. Apart from the well-known Wolff-Parkinson-White syndrome, a number of rare diseases are associated with pre-excitation due to the existence of accessory pathways. The present review aims to focus on anaesthesia and perioperative care of patients with rare genetic diseases associated with pre-excitation due to the existence of a bundle of Kent or other accessory pathways. The Danon disease, Fabry disease and Pompe disease, tuberous sclerosis, Leber hereditary optic neuropathy (LHON), and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome are genetic multisystem disorders which may involve pre-excitation, usually combined with cardiomyopathy. The anaesthetic management of the above syndromes may become quite challenging. We conducted a PubMed and manual literature search for all types of relevant publications; we identified 58 articles suitable to be included in the present review. According to the literature, a high index of suspicion for the possibility of pre-excitation is required, and anaesthetic drugs and adjuvants should be chosen carefully, in order to prevent or at least not facilitate arrhythmias associated with accessory pathways. The perioperative management should be further tailored to the specific abnormalities of each condition. Multidisciplinary consultation and care, according to the affected organs, are mandatory for a safe outcome. The anaesthetic plan should be focused on preoperative clinical optimization and on case-specific management, tailored to the various systems involved.

Electro-vectorcardiographic demonstration of bifascicular block associated with ventricular preexcitation.

Down syndrome occurs more frequently in the offsprings of older pregnant women and may be associated with atrioventricular septal defect. This refers to a broad spectrum of malformations characterized by a deficiency of the atrioventricular septum and abnormalities of the atrioventricular valves caused by an abnormal fusion of the superior and inferior endocardial cushions with the midportion of the atrial septum and the muscular portion of the ventricular septum.

Mutation in the γ2-subunit of AMP-activated protein kinase stimulates cardiomyocyte proliferation and hypertrophy independent of glycogen storage.

RATIONALE: AMP-activated protein kinase is a master regulator of cell metabolism and an attractive drug target for cancer and metabolic and cardiovascular diseases. Point mutations in the regulatory γ2-subunit of AMP-activated protein kinase (encoded by Prkag2 gene) caused a unique form of human cardiomyopathy characterized by cardiac hypertrophy, ventricular preexcitation, and glycogen storage. Understanding the disease mechanisms of Prkag2 cardiomyopathy is not only beneficial for the patients but also critical to the use of AMP-activated protein kinase as a drug target. OBJECTIVE: We sought to identify the pro-growth-signaling pathway(s) triggered by Prkag2 mutation and to distinguish it from the secondary response to glycogen storage. METHODS AND RESULTS: In a mouse model of N488I mutation of the Prkag2 gene (R2M), we rescued the glycogen storage phenotype by genetic inhibition of glucose-6-phosphate-stimulated glycogen synthase activity. Ablation of glycogen storage eliminated the ventricular preexcitation but did not affect the excessive cardiac growth in R2M mice. The progrowth effect in R2M hearts was mediated via increased insulin sensitivity and hyperactivity of Akt, resulting in activation of mammalian target of rapamycin and inactivation of forkhead box O transcription factor-signaling pathways. Consequently, cardiac myocyte proliferation during the postnatal period was enhanced in R2M hearts followed by hypertrophic growth in adult hearts. Inhibition of mammalian target of rapamycin activity by rapamycin or restoration of forkhead box O transcription factor activity by overexpressing forkhead box O transcription factor 1 rescued the abnormal cardiac growth. CONCLUSIONS: Our study reveals a novel mechanism for Prkag2 cardiomyopathy, independent of glycogen storage. The role of γ2-AMP-activated protein kinase in cell growth also has broad implications in cardiac development, growth, and regeneration.

Familial conduction system disease associated with hypertrophic cardiomyopathy.

A large family with a new phenotype of conduction system disease including heart blocks and preexcitation associated with hypertrophic cardiomyopathy and transmitted in an autosomal dominant pattern is described.

Is Wolff-Parkinson-White syndrome a genetic disease?

Family studies, and more recent molecular genetic investigations, indicate that the Wolff-Parkinson-White (WPW) syndrome and associated preexcitation disorders can have a substantial genetic component. Because preexcitation disorders are sometimes inherited as single gene disorders, key mechanistic insights can be gained that are expected to be relevant also to the more common multifactorial forms of these traits. Potentially, such insights will inform the future management of these conditions. Where WPW is inherited as a familial trait, with or without associated cardiac defects or a systemic syndrome, there are clinical genetic ramifications that are already of practical importance.

Electrophysiologic characterization and postnatal development of ventricular pre-excitation in a mouse model of cardiac hypertrophy and Wolff-Parkinson-White syndrome.

OBJECTIVES: We sought to characterize an animal model of the Wolff-Parkinson-White (WPW) syndrome to help elucidate the mechanisms of accessory pathway formation. BACKGROUND: Patients with mutations in PRKAG2 manifest cardiac hypertrophy and ventricular pre-excitation; however, the mechanisms underlying the development and conduction of accessory pathways remain unknown. METHODS: We created transgenic mice overexpressing either the Asn488Ile mutant (TG(N488I)) or wild-type (TG(WT)) human PRKAG2 complementary deoxyribonucleic acid under a cardiac-specific promoter. Both groups of transgenic mice underwent intracardiac electrophysiologic, electrocardiographic (ECG), and histologic analyses. RESULTS: On the ECG, approximately 50% of TG(N488I) mice displayed sinus bradycardia and features suggestive of pre-excitation, not seen in TG(WT) mice. The electrophysiologic studies revealed a distinct atrioventricular (AV) connection apart from the AV node, using programmed stimulation. In TG(N488I) mice with pre-excitation, procainamide blocked bypass tract conduction, whereas adenosine infusion caused AV block in TG(WT) mice but not TG(N488I) mice with pre-excitation. Serial ECGs in 16 mice pups revealed no differences at birth. After one week, two of eight TG(N488I) pups had ECG features of pre-excitation, increasing to seven of eight pups by week 4. By nine weeks, one TG(N488I) mouse with WPW syndrome lost this phenotype, whereas TG(WT) pups never developed pre-excitation. Histologic investigation revealed postnatal development of myocardial connections through the annulus fibrosum of the AV valves in young TG(N488I) but not TG(WT) mice. CONCLUSIONS: Transgenic mice overexpressing the Asn488Ile PRKAG2 mutation recapitulate an electrophysiologic phenotype similar to humans with this mutation. This includes procainamide-sensitive, adenosine-resistant accessory pathways induced in postnatal life that may rarely disappear later in life.

[Association between pre-excitation syndrome and 7q3 D7S505 pseudonym gene].

OBJECTIVE: Pre-excitation syndrome is considered to be autosomal dominant hereditary disease. The objective of this study was to search the genetic foundation of the pre-excitation syndrome. METHODS: Genomic DNA was isolated from peripheral lymphocytes obtained from 44 cases of patients with pre-excitation syndrome and 53 normal persons. Polymorphic short tandem repeats(STR) were amplified using polymerase chain reaction (PCR) and analyzed by polyacrylamide gel electrophoresis. The genotype of each individual was determined by polymorphic STR including D7S505,D7S688,D7S483. Association analysis between the pre-excitation syndrome and the 3 STR (D7S505,D7S483 and D7S688) was tested by genotyping. RESULTS: The relative risk(RR) of alleles A2 A3 A4 and A6 of D7S505 were 1.051 6, 3.432,1.563 1 and 1.714 3 respectively all of which were more than 1, but only the RR of A3 had statistic significant difference, P < 0.05 after tested by kappa(2). It supposed that the distribution of allele A3(266 bp) of D7S505 in patients with pre-excitation syndrome was much higher than that in normal controls, which suggested that pre-excitation syndrome is associated with D7S505. Whereas, there were no significant difference in every allele of D7S483 between the pre-excitation syndrome and normal persons, which suggested that pre-excitation syndrome is not associated with D7S483. CONCLUSION: The pre-excitation syndrome is associated with D7S505,the result is the foundation of the molecular genetics of the disease.

PRKAG2 cardiac syndrome: familial ventricular preexcitation, conduction system disease, and cardiac hypertrophy.

Genetic studies of families with inherited cardiac rhythm disturbances have established a molecular basis for ventricular arrhythmogenic disorders. Genes responsible for the long QT syndrome, Brugada syndrome, and polymorphic ventricular tachycardia have been identified. The elucidation of genetic defects responsible for more commonly occurring supraventricular rhythm disturbances have not been as forthcoming, with the exception of SCN5A mutations known to cause conduction system disease. Recently, we identified the genetic cause of a familial arrhythmogenic syndrome characterized by ventricular preexcitation and tachyarrhythmias (Wolff-Parkinson-White syndrome), progressive conduction system disease, and cardiac hypertrophy. The causative gene was shown to be the gamma-2 regulatory subunit (PRKAG2) of AMP-activated protein kinase. The role of AMP-activated protein kinase in the regulation of the glucose metabolic pathway in muscle suggests that genetic defects in PRKAG2 may induce a previously undescribed cardiac glycogenosis syndrome.

Familial Mahaim syndrome.

We describe the occurrence of Mahaim syndrome in a mother and her son. The occurrence of such a rare disorder in two members of a family is noteworthy, has not been reported before, and suggests the possibility of genetic transmission. A genetic transmission of supraventricular tachycardia has been described only in rare cases for the Wolff-Parkinson-White syndrome. No such data is available for the Mahaim syndrome.

[The familial incidence of accessory atrioventricular pathways (the pre-excitation syndrome)]. / Frecuencia familiar de vías accesorias atrioventriculares (síndrome de preexcitación).

Cases of familial preexcitation syndrome represent a specific subgroup of patients that may result from diverse mechanisms: failure in development and genetic predisposition are the main mechanism involved. We determined the prevalence of this syndrome in first degree relatives of patients with proved accessory pathways by electrophysiologic study and compared such prevalence with the general population (0.15%). In five out of 469 patients (1.06%) we found an accessory pathway in one or more member of their family. Only 6 out of 3752 had preexcitation (0.15%); this prevalence was similar to the general population (P = NS). The identification of family members with this syndrome may be incomplete because we only chose for the study symptomatic patients. We did not observed multiple pathways and in one case we found atrial septal defect. Our data demonstrated familial preexcitation in five families suggesting hereditary predisposition.

Frecuencia familiar de vías accesorias atrioventriculares (Síndrome de Preexcitación) / Familial frequency atrio-ventricular accessory pathways (Pre-excitation Syndrome)

Los casos de preexcitación familiar representan un subgrupo específico de personas en quienes la preexcitación resulta de más de un mecanismo etiológico; errores en el desarrollo y una predisposición genética son los principales mecanismos involucrados. Se determinó la prevalencia de preexcitación en los familiares en primer grado de 469 pacientes consecutivos con síndrome de Wolff-Parkinson-White comprobado electrofisiológicamente. Comparamos la prevalencia de preexcitación de los 3752 familiares en primer grado con la frecuencia observada en la población general (0.15 por ciento). En cinco pacientes con síndrome de Wolff-Parkinson-White (1.06 por ciento), se documentó una vía accesoria en uno o más de sus familiares en primer grado. Sólo 6 de los 3752 familiares en primer grado presentaron preexcitación (0.15); esta prevalencia fue similar a la reportada en la población general (P = NS). La identificación de familiares en primer grado puede ser incompleta debido a que sólo se tomaron para el estudio a familiares de pacientes sintomáticos con síndrome de Wolff-Parkinson-Whitte. No se observó la presencia de vías accesorias múltiples y en un solo caso se verificó la existencia de una comunicación interauricular

The preexcitation syndrome: epidemiological and genetic study.

A sample of 4210 subjects of both sexes aged 35-54 years was examined, chosen at random from six regions of Croatia. An electrocardiogram at rest was performed in all subjects and changes analyzed by the Minnesota code. A short P-R interval together with a widening QRS complex and a delta wave was found in 0.05%, while 42 (1.0%) of the examinees had a short P-R interval, but only 0.21% were symptomatic. Three years after the first examination 0.06% of the subjects had preexcitation with a delta wave, and in one subject it appeared after three years. 0.35% of the subjects had a short P-R interval after three years but only 0.18% were symptomatic and in 22 (0.65%) it had disappeared in three years. After 13 years these subjects did not appear for an examination, and the short P-R interval did not appear in any of other subjects during this period. There were more short P-R intervals: 3.22% in females and 1.96% in males, but 0.33% only were symptomatic. Antigens of the human leukocyte group A (HLA) system were analyzed in 46 patients: the Wolff-Parkinson-White syndrome was found in 35, while 11 had the Lown-Ganong-Levine syndrome. Antigens of the HLA-A, HLA-B and HLA-DR locuses were determined by the microlymphocytotoxicity method. The results of the frequency of HLA system antigens were compared to the results of the control group of a Croatian population consisting of 175 people. There was an increased frequency of HLA-A9 and HLA-B5 (P = 0.026 and 0.0092) in the investigated population as a whole. The participation of HLA-A3 antigen was significantly less among patients (P = 0.03), while HLA-B14 antigen was not found in patients with preexcitation. Within 10 HLA-DR locuses, HLA-DR7 antigen was rather more frequently present, although this was not statistically significant (P = 0.173).

[The inheritance of the ventricular pre-excitation syndrome]. / Nasledovanie sindroma prezhdevremennogo vozbuzhdeniia zheludochkov.

Medico-genetic studies including preparation of the family pedigree, interviews, examinations, electro- and echocardiography were carried out in the families of 75 patients with pre-excitation syndrome (PES). Of these, 35 patients presented with Wolff-Parkinson-White (WPW) syndrome and 40 with Clerc-Lévy-Cristesco (CLC) syndrome. The studies made in possible to define the autosomal-dominant type of the syndrome or PES inheritance and to diagnose for the first time WPW syndrome in 3, PES in 1, CLC syndrome in 32 and CLC phenomenon in 89 persons out of 233 relatives of the first and second degree kinship.