Detection of giant cytoplasmic inclusions in a pediatric patient with recurrent infections: a case report.

Objectives: Giant inclusions in leukocytes is a common feature that can be observed in some infections but can be also related to rare genetic disorders such as Chédiak-Higashi syndrome (CHS). A differential diagnosis between these groups of diseases has to be performed using specific genetic tests. Clinical and pathological history is relevant for a diagnostic orientation due to the difficulty and specificity of the diagnostic confirmation. Case presenation: We present the case of a 3-years-old male patient with recurrent respiratory infections. It is important to highlight the presence of a lock of white hair on the front of the head and some hypopigmentation of the skin. In the blood smear, the presence of big cytoplasm granules in all the leukocytes, especially in neutrophils. Conclusions: CHS is an uncommon genetic disorder caused by the mutation in the LYST gene situated in chromosome 1q42.3 which codified for LYST protein. Molecular genetic testing also can be done to detect the biallelic variants in the LYST gene. It is essential to perform peripheral blood smears in the presence of changes in quantitative and/or qualitative values in the complete blood count as a first step in the diagnosis algorithm.

Familial 4.8 MB deletion on 18q23 associated with growth hormone insufficiency and phenotypic variability.

The deletion of the long arm of chromosome 18 causes a contiguous gene deletion syndrome with a highly variable phenotype, usually related to the extent of the deleted region. The most commonly reported clinical features include: decreased growth, microcephaly, facial abnormalities, hypotonia, developmental delay, intellectual disability, congenital aural atresia with hearing impairment and limb anomalies. Here we report on a familial terminal deletion of 18q23 region transmitted from a mother to two daughters, resulting in a remarkable phenotypic variability. The deletion was first detected by conventional cytogenetic analysis in one daughter and subsequently characterized using fluorescence in situ hybridization (FISH) and array-CGH. FISH analysis using subtelomeric 18p and 18q probes confirmed the 18qter deletion in the three patients, and FISH with a whole chromosome painting probe specific for chromosome 18 excluded rearrangements with other chromosomes. Array-CGH analysis allowed us to precisely define the extent of the deletion, which spans 4.8 Mb from 71,236,891 to 76,093,303 genomic positions and includes GALR1 and MBP genes, among others. High-resolution analysis of the deletion, besides a detailed clinical assessment, has provided important data for phenotype-genotype correlation and genetic counseling in this family. Furthermore, this study adds valuable information for phenotype-genotype correlation in 18q- syndrome and might facilitate future search for candidate genes involved in each phenotypic trait.

Targeted next-generation sequencing provides novel clues for associated epilepsy and cardiac conduction disorder/SUDEP.

Sudden unexpected death in epilepsy is an unpredicted condition in patients with a diagnosis of epilepsy, and autopsy does not conclusively identify cause of death. Although the pathophysiological mechanisms that underlie this entity remain unknown, the fact that epilepsy can affect cardiac function is not surprising. The genetic factors involving ion channels co-expressed in the heart and brain and other candidate genes have been previously described. In the present study, 20 epilepsy patients with personal or family history of heart rhythm disturbance/cardiac arrhythmias/sudden death were sequenced using a custom re-sequencing panel. Twenty-six relatives were genetically analysed to ascertain the family segregation in ten individuals. Four subjects revealed variants with positive genotype-phenotype segregation: four missense variants in the CDKL5, CNTNAP2, GRIN2A and ADGRV1 genes and one copy number variant in KCNQ1. The potential pathogenic role of variants in new candidate genes will need further studies in larger cohorts, and the evaluation of the potential pathogenic role in the cardio-cerebral mechanisms requires in vivo/in vitro studies. In addition to family segregation, evaluation of the potential pathogenic roles of these variants in cardio-cerebral mechanisms by in vivo/in vitro studies should also be performed. The potential pathogenic role of variants in new candidate genes will need further studies in larger cohorts.

A novel variant in RyR2 causes familiar catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia is a rare familial arrhythmogenic disease. It usually occurs in juvenile patients with a structurally normal heart and causes exercise-emotion triggered syncope and sudden cardiac death. The main gene associated with catecholaminergic polymorphic ventricular tachycardia is RyR2, encoding the cardiac ryanodine receptor protein which is involved in calcium homeostasis. After the identification of a 16 year-old man presenting with exercise-induced sudden cardiac death, clinically diagnosed as catecholaminergic polymorphic ventricular tachycardia, we collected the family information and performed a comprehensive genetic analysis using Next Generation Sequencing technology. The initial electrocardiogram in the emergency department revealed ventricular fibrillation. On electrocardiogram monitoring, sinus tachycardia degenerated into bidirectional ventricular and into ventricular fibrillation. Catecholaminergic polymorphic ventricular tachycardia was clinically diagnosed in 5 of the 14 family members evaluated. There were no additional reports of seizures, pregnancy loss, neonatal death, or sudden cardiac death in family members. Genetic analysis of the index case identified only one rare novel variant p.Ile11Ser (c.32T>G) in the RyR2 gene. Subsequent familial analysis identified segregation of the genetic variant with the disease. All current evidence supports that novel p.Ile11Ser variant in the RyR2 gene is a potential disease-causing variant in catecholaminergic polymorphic ventricular tachycardia. To our knowledge, there has been no previous case report of catecholaminergic polymorphic ventricular tachycardia associated to this missense variant.

Correction: Natural and Undetermined Sudden Death: Value of Post-Mortem Genetic Investigation.

[This corrects the article DOI: 10.1371/journal.pone.0167358.].

Natural and Undetermined Sudden Death: Value of Post-Mortem Genetic Investigation.

BACKGROUND: Sudden unexplained death may be the first manifestation of an unknown inherited cardiac disease. Current genetic technologies may enable the unraveling of an etiology and the identification of relatives at risk. The aim of our study was to define the etiology of natural deaths, younger than 50 years of age, and to investigate whether genetic defects associated with cardiac diseases could provide a potential etiology for the unexplained cases. METHODS AND FINDINGS: Our cohort included a total of 789 consecutive cases (77.19% males) <50 years old (average 38.6±12.2 years old) who died suddenly from non-violent causes. A comprehensive autopsy was performed according to current forensic guidelines. During autopsy a cause of death was identified in most cases (81.1%), mainly due to cardiac alterations (56.87%). In unexplained cases, genetic analysis of the main genes associated with sudden cardiac death was performed using Next Generation Sequencing technology. Genetic analysis was performed in suspected inherited diseases (cardiomyopathy) and in unexplained death, with identification of potentially pathogenic variants in nearly 50% and 40% of samples, respectively. CONCLUSIONS: Cardiac disease is the most important cause of sudden death, especially after the age of 40. Close to 10% of cases may remain unexplained after a complete autopsy investigation. Molecular autopsy may provide an explanation for a significant part of these unexplained cases. Identification of genetic variations enables genetic counseling and undertaking of preventive measures in relatives at risk.

Further evidence of the association between LQT syndrome and epilepsy in a family with KCNQ1 pathogenic variant.

PURPOSE: Ion channels are expressed both in the heart and in the brain, being advocated as responsible for sudden unexpected death in epilepsy but few pathogenic mutations have been identified. We aim to identify a novel gen associated with channelopathies and epilepsy in a family. METHODS: We assessed a family showing epilepsy concomitant with LQTS. Index case showed prolonged QT interval. His father suffers of LQT and epilepsy. We performed a direct sequencing analysis of KCNQ1, KCNH2, KCNE1, KCNE2 and SCN5A genes. RESULTS: We identified a non-synonymous heterozygous missense pathogenic mutation (p.L273F) in exon 6 of the KCNQ1 gene. All clinically affected relatives carried the same mutation. CONCLUSION: We report, for a first time, a KCNQ1 mutation in a family suffering of both phenotypes, suggesting that KCNQ1 genetic variations may confer susceptibility for recurrent seizure activity increasing the risk or lead to sudden death.