Neurological Manifestations of X-Linked Ichthyosis: Case Report and Review of the Literature

A 5-year-old boy presented with mild autism and attention-deficit hyperactivity disorder (ADHD). Chromosomal microarray demonstrated a 1.7 Mb deletion at Xp22.31, which was consistent with X-linked ichthyosis (XLI). Further exam revealed dry, scaly skin on his abdomen and pretibial areas. Patients with mutations involving solely the STS gene or the recurrent ~2 Mb deletion may present with ADHD, whereas those with larger deletions including the NLGN4 gene can present with both ADHD and autism. However, our patient presented with mild autism in addition to ADHD despite having only the recurrent deletion without loss of NLGN4. Such neurological manifestations of XLI warrant attention as practical targets of clinical management

Inhibition of Replication of T2 Bacteriophage in Escherichia coli by 6-diazo-5-oxo-Lnorleucine (DON)

The antibiotic known as 6-diazo-5-oxo-L-norleucine, DON, inhibits the growth of several types of Gram positive and Gram negative bacteria. It has also been demonstrated that DON inhibits the replication of poliovirus, respiratory syncytial virus, mumps and herpes simplex virus in cultured eukaryotic cells. At a concentration of 0.03 mM DON, the replication of Escherichia coli cells was inhibited by 11.0% after 2 h of growth. In cultures of E. coli, cells infected with T2 bacteriophage and treated with 0.03 mM DON, the yield of T2 bacteriophage decreased by 88.0%. In E. coli, cells infected with T2 bacteriophage and treated with 0.03 mM DON, the addition of 45 mM glutamine completely reversed the DON inhibition of T2 bacteriophage replication. Likewise, adding a 15 mM concentration each of adenosine, cytidine, guanosine, and thymidine reversed the DON inhibition of T2 bacteriophage replication by 65%. Conversely, the addition of as much as 15 mM glucosamine had no effect on the DON inhibition of T2 bacteriophage replication in treated E. coli cells. These results suggest that DON inhibits the replication of T2 bacteriophage in E. coli cells by inhibiting the metabolism of glutamine and/or nucleosides during viral replication but not glycoprotein synthesis

Compound heterozygosity with a novel S222N GALT mutation leads to atypical galactosemia with loss of GALT activity in erythrocytes but little evidence of clinical disease

Galactosemia is an inborn error of galactose metabolism caused by mutations in the GALT gene. Though early detection and galactose restriction prevent severe liver disease, affected individuals have persistently elevated biomarkers and often neuro-developmental symptoms. We present a teenage compound heterozygote for a known pathogenic mutation (H132Q) and a novel variant of unknown significance (S222N), with nearly absent erythrocyte GALT enzyme activity but normal biomarkers and only mild anxiety despite diet non-adherence. This case is similar to a previously reported S135L mutation. In this report we investigate the novel S222N variant and critically evaluate a clinically puzzling case

Biochemical and computational analyses of two phenotypically related GALT mutations (S222N and S135L) that lead to atypical galactosemia

Galactosemia is a metabolic disorder caused by mutations in the GALT gene [1,2]. We encountered a patient heterozygous for a known pathogenic H132Q mutation and a novel S222N variant of unknown significance [3]. Reminiscent of patients with the S135L mutation, our patient had loss of GALT enzyme activity in erythrocytes but a very mild clinical phenotype [3–8]. We performed splicing experiments and computational structural analyses to investigate the role of the novel S222N variant. Alamut software data predicted loss of splicing enhancers for the S222N and S135L mutations [9,10]. A cDNA library was generated from our patient׳s RNA to investigate for splicing errors, but no change in transcript length was seen [3]. In silico structural analysis was performed to investigate enzyme stability and attempt to understand the mechanism of the atypical galactosemia phenotype. Stability results are publicly available in the GALT Protein Database 2.0 [11–14]. Animations were created to give the reader a dynamic view of the enzyme structure and mutation locations. Protein database files and python scripts are included for further investigation

Genetic and Epigenetic Changes in Chromosomally Stable and Unstable Progeny of Irradiated Cells

<div><p>Radiation induced genomic instability is a well-studied phenomenon, the underlying mechanisms of which are poorly understood. Persistent oxidative stress, mitochondrial dysfunction, elevated cytokine levels and epigenetic changes are among the mechanisms invoked in the perpetuation of the phenotype. To determine whether epigenetic aberrations affect genomic instability we measured DNA methylation, mRNA and microRNA (miR) levels in well characterized chromosomally stable and unstable clonally expanded single cell survivors of irradiation. While no changes in DNA methylation were observed for the gene promoters evaluated, increased LINE-1 methylation was observed for two unstable clones (LS12 and CS9) and decreased Alu element methylation was observed for the other two unstable clones (115 and Fe5.0–8). These relationships also manifested for mRNA and miR expression. mRNA identified for the LS12 and CS9 clones were most similar to each other (261 mRNA), while the 115 and Fe5.0–8 clones were more similar to each other, and surprisingly also similar to the two stable clones, 114 and 118 (286 mRNA among these four clones). Pathway analysis showed enrichment for pathways involved in mitochondrial function and cellular redox, themes routinely invoked in genomic instability. The commonalities between the two subgroups of clones were also observed for miR. The number of miR for which anti-correlated mRNA were identified suggests that these miR exert functional effects in each clone. The results demonstrate significant genetic and epigenetic changes in unstable cells, but similar changes are almost as equally common in chromosomally stable cells. Possible conclusions might be that the chromosomally stable clones have some other form of instability, or that some of the observed changes represent a sort of radiation signature and that other changes are related to genomic instability. Irrespective, these findings again suggest that a spectrum of changes both drive genomic instability and permit unstable cells to persist and proliferate.</p></div

Human <i>NFκB</i> methylation status.

<p>Representative gels for A) methylation sensitive PCR of bisulfite modified DNA for the <i>NFκB</i> promoter; B) PCR of unmodified genomic DNA; and C) methylation sensitive PCR of bisulfite modified DNA for <i>TSLC1</i> and <i>CDH1</i> promoter methylation. D) Bisulfite sequencing for <i>NFκB</i> promoter. ‘L’ lanes indicate molecular weight ladders, ‘u’ lanes indicate PCR using primers specific to unmethylated promoter sequences; ‘m’ lanes indicate PCR using primers specific to methylated promoter sequences; ‘u+’ and ‘m+’ indicate respective positive control PCRs; the H2O lane indicates a PCR control containing no DNA template; open circles indicate unmethylated CpG; dashes indicate that no data was obtained).</p

Overlap in gene expression profiles.

<p>The differentially regulated genes represented in each Venn diagram were identified with multiple testing and false discovery rate statistics at <i>P</i><0.05. Three replicate arrays were performed and the significance threshold was set at <i>P</i><0.05.</p

Overlap in miR expression profiles.

<p>Preliminary statistical analyses were performed on raw data normalized by the LOWESS method on the background-subtracted data. ANOVA were then performed to identify differences in miR expression. Two replicate arrays were performed, so the significance threshold was set at <i>P</i><0.10.</p