Genetic investigation of 93 families with microphthalmia or posterior microphthalmos

Microphthalmia is a developmental eye defect that is highly variable in severity and in its potential for systemic association. Despite the discovery of many disease genes in microphthalmia, at least 50% of patients remain undiagnosed genetically. Here, we describe a cohort of 147 patients (93 families) from our highly consanguineous population with various forms of microphthalmia (including the distinct entity of posterior microphthalmos) that were investigated using a next‐generation sequencing multi‐gene panel (i‐panel) as well as whole exome sequencing and molecular karyotyping. A potentially causal mutation was identified in the majority of the cohort with microphthalmia (61%) and posterior microphthalmos (82%). The identified mutations (55 point mutations, 15 of which are novel) spanned 24 known disease genes, some of which have not or only very rarely been linked to microphthalmia (PAX6, SLC18A2, DSC3 and CNKSR1). Our study has also identified interesting candidate variants in 2 genes that have not been linked to human diseases (MYO10 and ZNF219), which we present here as novel candidates for microphthalmia. In addition to revealing novel phenotypic aspects of microphthalmia, this study expands its allelic and locus heterogeneity and highlights the need for expanded testing of patients with this condition.     

3-Hydroxy-3-methylglutaric aciduria: Response to carnitine therapy and fat and leucine restriction

A female infant, born to first cousin parents, lapsed into coma with severe metabolic acidosis on day three of life. The gas chromatographic/mass spectrometric urinary organic acid profile showed marked elevation of the leucine metabolites 3-hydroxy-3-methylglutaric, 3-methylglutaconic, 3-methylglutaric and 3-hydroxy-isovaleric acids. Less than 5% of the normal activity of the enzyme 3-hydroxy-3-methylglutaryl CoA lyase was detected in cultured skin fibroblasts. The patient's total and free carnitine was initially low but rose to normal levels after placing her ondl-carnitine (100 mg kg^–1 d^–1). On a diet providing 87 mg kg^–1 d^–1 of leucine and only 25% of total calories as fat and 2 g kg^–1 d^–1 protein, the concentration of the urinary organic acids fell markedly. She is now 15 months old with normal growth and development. This regimen appears effective in the early treatment of 3-hydroxy-3-methylglutaric aciduria.     

Acupuncture therapy for sleep-related laryngospasm

Sleep-related laryngospasm is a rare disorder that may cause severe disablement. It refers to episodic arousal from sleep with a sense of suffocation followed by stridor. This phenomenon, which is caused by laryngospasm, is probably secondary to gastroesophageal reflux. The reflux is the target for current treatment of this serious disorder. Treatment by acupuncture for sleep-related laryngospasm has not been previously reported in the English medical literature. We describe a previously healthy patient with sleep-related laryngospasm caused by gastroesophageal reflux refractory to current medical treatment who was treated successfully using acupuncture.     

Alterations of platelet function and clot formation kinetics after in vitro exposure to anti‐A and ‐B

BACKGROUND: ABO‐mismatched platelets (PLTs) are commonly transfused despite reported complications. We hypothesized that because PLTs possess A and B antigens on their surface, ABO‐mismatched transfused or recipient PLTs could become activated and/or dysfunctional after exposure to anti‐A or ‐B in the transfused or recipient plasma. We present here in vitro modeling data on the functional effects of exposure of PLTs to ABO antibodies. STUDY DESIGN AND METHODS: PLT functions of normal PLTs of all ABO types were assessed before and after incubation with normal saline, ABO‐identical plasma samples, or O plasma samples with varying titers of anti‐A and anti‐B (anti‐A/B). Assays used for this assessment include PLT aggregation, clot kinetics, thrombin generation, PLT cytoskeletal function, and mediator release. RESULTS: Exposure of antigen‐bearing PLTs to O plasma with moderate to high titers of anti‐A/B significantly inhibits aggregation, prolongs PFA‐100 epinephrine closure time, disrupts clot formation kinetics, accelerates thrombin generation, reduces total thrombin production, alters PLT cytoskeletal function, and influences proinflammatory and prothrombotic mediator release. CONCLUSIONS: Our findings demonstrate a wide range of effects that anti‐A/B have on PLT function, clot formation, thrombin generation, PLT cytoskeletal function, and mediator release. These data provide potential explanations for clinical observations of increased red blood cell utilization in trauma and surgical patients receiving ABO‐nonidentical blood products. Impaired hemostasis caused by anti‐A/B interacting with A and B antigens on PLTs, soluble proteins, and perhaps even endothelial cells is a potential contributing factor to hemorrhage in patients receiving larger volumes of ABO‐nonidentical transfusions.     

Relationship between tumor necrosis factor‐alpha and ammonia in patients with hepatic encephalopathy due to chronic liver failure

BACKGROUND. We have recently demonstrated that in humans, circulating levels of tumor necrosis factor‐α (TNF) correlate positively with severity of hepatic encephalopathy (HE) due to chronic liver failure.

AIM. The main aim of this larger population study is to determine the relationship between TNF and ammonia in patients with HE and chronic liver failure due to liver cirrhosis.

METHODS. Circulating levels of TNF and ammonia were measured in 108 patients with liver cirrhosis due to various etiologies in various clinical grades of HE (grades 0–4). TNF concentrations were measured in venous serum using commercially available solid‐phase high sensitivity enzyme‐linked immunosorbent assay. Ammonia levels were determined in venous plasma by the enzymatic method, using the glutamate dehydrogenase reaction.

RESULTS. The mean±SEM values of circulating levels of TNF and ammonia at presentation in patients with grade 0 of HE (n = 30) were 3.89±0.2?pg/mL and 49.8±2.8?µg/mL respectively, in patients with grade 1 of HE (n = 26) were 8.56±0.34?pg/mL and 101.6±6.5?µg/mL respectively, in patients with grade 2 of HE (n = 22) were 11.59±0.48?pg/mL and 160.3±10.7?µg/mL respectively, in patients with grade 3 of HE (n = 20) were 19.98±0.94?pg/mL and 228.8±16.1?µg/mL respectively, and in patients with grade 4 of HE (n = 10) were 51.53±8.59?pg/mL and 284.2±20.3?µg/mL respectively. A significant positive correlation was found between circulating levels of TNF and those of ammonia (r = 0.62, P<0.0001), and also between circulating levels of both substances and severity of HE in these patients (r = 0.95, P<0.0001, and r = 0.9, P<0.0001 respectively). TNF and ammonia were both significant independent predictors of severity of HE (P<0.0001 for both variables).

CONCLUSION. The results of this study demonstrate a significant relationship between TNF and ammonia in patients with chronic liver failure and HE, and so strengthen the suggestion that TNF could be strongly involved in the pathogenesis of HE in these patients. Hence, we suggest a new theory in the pathogenesis of HE, the ‘TNF theory’.