Identification, clinical manifestation and structural mechanisms of mutations in AMPK associated cardiac glycogen storage disease

BACKGROUND: Although 21 causative mutations have been associated with PRKAG2 syndrome, our understanding of the syndrome remains incomplete. The aim of this project is to further investigate its unique genetic background, clinical manifestations, and underlying structural changes. METHODS: We recruited 885 hypertrophic cardiomyopathy (HCM) probands and their families internationally. Targeted next-generation sequencing of sudden cardiac death (SCD) genes was performed. The role of the identified variants was assessed using histological techniques and computational modeling. FINDINGS: Twelve PRKAG2 syndrome kindreds harboring 5 distinct variants were identified. The clinical penetrance of 25 carriers was 100.0%. Twenty-two family members died of SCD or heart failure (HF). All probands developed bradycardia (HRmin, 36.3+/-9.8bpm) and cardiac conduction defects, and 33% had evidence of atrial fibrillation/paroxysmal supraventricular tachycardia (PSVT) and 67% had ventricular preexcitation, respectively. Some carriers presented with apical hypertrophy, hypertension, hyperlipidemia, and renal insufficiency. Histological study revealed reduced AMPK activity and major cardiac channels in the heart tissue with K485E mutation. Computational modelling suggests that K485E disrupts the salt bridge connecting the beta and gamma subunits of AMPK, R302Q/P decreases the binding affinity for ATP, T400N and H401D alter the orientation of H383 and R531 residues, thus altering nucleotide binding, and N488I and L341S lead to structural instability in the Bateman domain, which disrupts the intramolecular regulation. INTERPRETATION: Including 4 families with 3 new mutations, we describe a cohort of 12 kindreds with PRKAG2 syndrome with novel pathogenic mechanisms by computational modelling. Severe clinical cardiac phenotypes may be developed, including HF, requiring close follow-up

The complete spectrum of pentalogy of Cantrell in one of a set of dizygotic twins: A case report of a rare congenital anomaly.

Pentalogy of Cantrell (POC) is an extremely rare syndrome with an estimated incidence of 1:65,000 to 200,000 live births. Its complete form includes a midline epigastric abdominal wall defect, defects affecting the lower sternum, anterior diaphragm, diaphragmatic pericardium, and various intracardiac defects. We report a case of complete POC affecting only the first-born of a set of premature dizygotic twins. A giant omphalocele with an eviscerated liver and bowel on prenatal, obstetric ultrasonography at 24 gestational weeks was observed. At birth, physical examination confirmed a massive (10 × 8 cm) epigastric omphalocele in which a significant part of the liver was seen. A postnatal echocardiogram revealed the presence of an ostium secundum atrial septal defect, perimembranous ventricular septal defect, and moderate pulmonary stenosis. X-ray showed an abnormal intrathoracic positioned stomach, which was confirmed with a plain x-ray of the upper intestinal tract with hydrosoluble contrast. Computed tomography (CT) scan revealed the sternum's absence and a close connection between the pericardial sac and the stomach wall. The patient underwent surgical intervention at 18 days of age. Despite adequate and appropriate postoperative treatment, the baby rapidly deteriorated and died 72 hours after surgery. POC is a complex, high-mortality syndrome whose management requires a multidisciplinary approach and meticulous planning. Despite all efforts, POC carries a poor prognosis, particularly in patients affected by its complete form.Qatar National Librar

Identification, clinical manifestation and structural mechanisms of mutations in AMPK associated cardiac glycogen storage disease

BACKGROUND: Although 21 causative mutations have been associated with PRKAG2 syndrome, our understanding of the syndrome remains incomplete. The aim of this project is to further investigate its unique genetic background, clinical manifestations, and underlying structural changes. METHODS: We recruited 885 hypertrophic cardiomyopathy (HCM) probands and their families internationally. Targeted next-generation sequencing of sudden cardiac death (SCD) genes was performed. The role of the identified variants was assessed using histological techniques and computational modeling. FINDINGS: Twelve PRKAG2 syndrome kindreds harboring 5 distinct variants were identified. The clinical penetrance of 25 carriers was 100.0%. Twenty-two family members died of SCD or heart failure (HF). All probands developed bradycardia (HRmin, 36.3 ± 9.8 bpm) and cardiac conduction defects, and 33% had evidence of atrial fibrillation/paroxysmal supraventricular tachycardia (PSVT) and 67% had ventricular preexcitation, respectively. Some carriers presented with apical hypertrophy, hypertension, hyperlipidemia, and renal insufficiency. Histological study revealed reduced AMPK activity and major cardiac channels in the heart tissue with K485E mutation. Computational modelling suggests that K485E disrupts the salt bridge connecting the β and γ subunits of AMPK, R302Q/P decreases the binding affinity for ATP, T400N and H401D alter the orientation of H383 and R531 residues, thus altering nucleotide binding, and N488I and L341S lead to structural instability in the Bateman domain, which disrupts the intramolecular regulation. INTERPRETATION: Including 4 families with 3 new mutations, we describe a cohort of 12 kindreds with PRKAG2 syndrome with novel pathogenic mechanisms by computational modelling. Severe clinical cardiac phenotypes may be developed, including HF, requiring close follow-up