A de novo germline RUNX1 variant preceding development of concurrent T-lymphoblastic leukemia and myelodysplastic syndrome.

Germline variants of the RUNX1 gene are associated with RUNX1 Familial Platelet Disorder with Associated Myeloid Malignancies (RUNX1-FPDMM), which is characterized by an increased risk of developing myelodysplastic syndrome (MDS) and/or acute myeloid leukemia. Patients with FPDMM have also been described to develop B- or T-cell acute lymphoblastic leukemia. We present a pediatric patient with RUNX1-FPDMM that evolved into concurrent MDS and T-cell acute lymphoblastic leukemia after a decade of monitoring with serial blood counts. We aim to highlight the treatment challenges and clinical decision-making that may be anticipated in this unique disorder, as well as the potentially curative role for allogenic hematopoietic stem cell transplant in the first complete remission.

Myocardial Infarction in the Neonate Without Coronary Artery Occlusion and Structurally Normal Heart: A Report of 2 Cases in Twin Pregnancies and Review of the Literature.

Myocardial infarction (MI) is a common diagnosis in the adult population and is associated with coronary artery atherosclerosis. However, it is an unusual diagnosis in the pediatric population, especially in the neonatal period. The authors present 2 autopsy cases of MI in newborn babies of twin pregnancies with normal heart and coronary arteries. The first case is that of a 10-day-old female, monochorionic-diamniotic, twin B born at 29 weeks' gestation. The autopsy revealed diffuse subacute MI in both ventricles, which was compatible with a global hypoxic event during perinatal period. The hypoxic insult was likely caused by maternal HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome as evident in the placental examination, which showed placental infarct and decidual arteriopathy. The second case is that of a 2-day-old term male, dichorionic-diamniotic, twin A with an antenatal history of prolonged rupture of membranes. The hospital course was complicated by neonatal sepsis. The autopsy showed diffuse hemorrhage in the internal organs including the heart, along with myocyte necrosis. The overall findings were consistent with multiorgan dysfunction syndrome resulting from sepsis. Previous reported cases of MI in neonates without coronary artery occlusion were also reviewed and portrayed.

Decreased exercise capacity and sleep-disordered breathing in patients with hypertrophic cardiomyopathy.

BACKGROUND: Mechanisms of decreased exercise capacity in patients with hypertrophic cardiomyopathy (HCM) are not well understood. Sleep-disordered breathing (SDB) is a highly prevalent but treatable disorder in patients with HCM. The role of comorbid SDB in the attenuated exercise capacity in HCM has not been studied previously. METHODS: Overnight oximetry, cardiopulmonary exercise testing, and echocardiographic studies were performed in consecutive patients with HCM seen at the Mayo Clinic. SDB was considered present if the oxygen desaturation index (number of ≥ 4% desaturations/h) was ≥ 10. Peak oxygen consumption (VO2 peak) (the most reproducible and prognostic measure of cardiovascular fitness) was then correlated with the presence and severity of SDB. RESULTS: A total of 198 patients with HCM were studied (age, 53 ± 16 years; 122 men), of whom 32% met the criteria for the SDB diagnosis. Patients with SDB had decreased VO2 peak compared with those without SDB (16 mL O2/kg/min vs 21 mL O2/kg/min, P < .001). SDB remained significantly associated with VO2 peak after accounting for confounding clinical variables (P < .001) including age, sex, BMI, atrial fibrillation, and coronary artery disease. CONCLUSIONS: In patients with HCM, the presence of SDB is associated with decreased VO2 peak. SDB may represent an important and potentially modifiable contributor to impaired exercise tolerance in this unique population.