Identification of novel compound heterozygous variants in SLC19A2 and the genotype-phenotype associations in thiamine-responsive megaloblastic anemia.

BACKGROUND AND AIMS: Thiamine-responsive megaloblastic anemia (TRMA), caused by SLC19A2 loss-of-function variants, is characterized by the triad of megaloblastic anemia, progressive sensorineural deafness, and non-type 1 diabetes mellitus. Here, we present the case of a Chinese infant with two novel variants segregating in compound heterozygous form in SLC19A2 and reviewed genotype-phenotype associations (GPAs) in patients with TRMA. MATERIALS AND METHODS: Whole-exome sequencing was performed to establish a genetic diagnosis. The clinical manifestations and genetic variants were collected by performing a literature review. The bioinformatics software SIFT, PolyPhen2, and Mutation Taster was applied to predict variant effects and analyze GPAs. RESULTS: Two novel variants segregating in compound heterozygous form in SLC19A2 (NM_006996.2: exon2:c.336_363del:p.W112fs; exon2:c.358G>T:p.G120X) was identified. Thiamine supplementation corrected anemia and diabetes mellitus but did not improve the hearing defect. In the literature, 183 patients with TRMA with 74 variants in SLC19A2 have been reported, with high incidence in the Middle East, South Asia, and the northern Mediterranean. Patients with biallelic premature termination codon variants presented with more severe phenotypes, and truncating sites on extracellular domains was a protective factor for the hemoglobin level at diagnosis. CONCLUSION: Two novel compound heterozygous variants (NM_006996.2: exon2:c.336_363del:p.W112fs; exon2:c.358G>T:p.G120X) were identified, and GPAs in TRMA indicated the predictability of clinical manifestations.

[Efficacy of letrozole in treatment of children with congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency].

OBJECTIVE: To assess the efficacy of letrozole in treatment of children with congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency (21-OHD). METHODS: Twenty eight children, including 19 boys and 9 girls aged 4-10y, with CAH due to 21-OHD were enrolled in the study. At the first six months of study, all children received conventional treatment with hydrocortisone or fludrocortisone, then letrozole was added to original regimen. The height velocity (HV), difference between bone age and chronological age (BA-CA), height standard diviation score based on bone age (HtSDS BA), predicted adult height (PAH), Tanner phase, sex hormone, and possible adverse reaction were evaluated and compared between those before and after letrozole treatment. RESULTS: After 6 months of letrozole treatment, there was significant deceleration of HV, but it would recover soon. There was significant increase of HtSDS BA after 12 months of letrozole treatment ( P < 0.05 or P < 0.01), and significant changes in BA-CA after 18 months of letrozole treatment ( P < 0.05). PAH of female children was significantly increased during letrozole treatment ( P < 0.05), whereas PAH of male children was significantly increased 18 months after letrozole treatment ( P < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly increased, but did not meet the diagnostic criteria of central precocious puberty. Estradiol was significantly decreased ( P < 0.01), but no changes in testosterone level was observed. During 24 months letrozole treatment, no hirsutism, severe acne, headache, bone pain, obesity, hypertension, rash and other adverse reactions were observed. CONCLUSIONS: Letrozole can delay bone maturation and improve PAH, which can be used with conventional treatment for children with CAH due to 21-OHD, especially for those with high BA and low PAH.

Growth and Adult Height during Human Growth Hormone Treatment in Chinese Children with Multiple Pituitary Hormone Deficiency Caused by Pituitary Stalk Interruption Syndrome: A Single Centre Study

Objective: The aim was to assess growth velocity (GV) during human recombinant growth hormone (hGH) treatment of children with multiple pituitary hormone deficiency (MPHD) caused by pituitary stalk interruption syndrome (PSIS) and to analyze the characteristics of patients that attained normal adult heights. Methods: Data from 74 (16 female) children with MPHD caused by PSIS with GH, thyroid stimulating hormone, gonadotropin and adrenocorticotropic hormone deficiencies were collected. Subjects were divided into groups: 12 pre-pubescent females (Female-Group) and 36 pre-pubescent males (Male-Group 1). The remaining 22 males were further sub-divided into two groups (Male-Group 2 and Male-Group 3) according to the initiation of gonadotropin replacement treatment, based on bone age and height. Results: No differences in change in height standard deviation score (△HtSDS) and GV were observed at different time points of hGH treatment between the Female-Group and Male-Group 1 (p>0.05). GV was significantly greater in the first year of hGH therapy than in subsequent years: Female-Group p=0.011; Male-Group 1 p<0.001; Male-Group 2 p=0.005; and Male-Group 3 p=0.046. Adult height was achieved by 23 (19 males and 4 females) patients. The total gain in height positively correlated with the GV during the first year (r=0.626, p<0.001). Conclusion: GV during hGH treatment were similar amongst pre-pubescent males and females with MPHD caused by PSIS. GV during the first year of hGH treatment appears to be an effective predictor of final height in patients with MPHD caused by PSIS.

Use of PEGylated Recombinant Human Growth Hormone in Chinese Children with Growth Hormone Deficiency: A 24-Month Follow-Up Study.

OBJECTIVE: Once-weekly PEGylated recombinant human growth hormone (rhGH) is the sole long-acting GH formulation available currently for pediatric patients with GH deficiency (GHD). The aim of this study was to evaluate the efficacy and safety of PEGylated rhGH therapy compared to daily rhGH therapy in GHD children treated for two years. METHODS: A total of 98 children (49 children for the PEGylated rhGH group and 49 children for the daily rhGH group) with GHD were enrolled in this single-center, prospective, nonrandomized cohort study. PEGylated rhGH or daily rhGH was administered for 2 years. Height, height SDS, height velocity (HV), IGF-1, bone age (BA), and adverse events were determined throughout the treatment. RESULTS: HV significantly increased over the baseline and was similar in both groups. In the PEGylated rhGH cohort, the mean ± SD HV was improved from 3.78 ± 0.78 cm/y at the baseline to 12.44 ± 3.80 cm/y at month 3, to 11.50 ± 3.01 cm/y at month 6, to 11.00 ± 2.32 cm/y at month 12, and finally 10.08 ± 2.12 cm/y at month 24 in the PEGylated rhGH group. In the daily rhGH group, HV was 3.36 ± 1.00 cm/y at baseline, increasing to 12.56 ± 3.71 cm/y at month 3, to 11.82 ± 2.63 cm/y at month 6, to 10.46 ± 1.78 cm/y at month 12, and to 9.28 ± 1.22 cm/y at month 24. No serious adverse event related to PEGylated rhGH or daily rhGH occurred during the 24-month study. CONCLUSION: PEGylated rhGH replacement therapy is effective and safe in pediatric patients with GHD. The adherence to once-weekly PEGylated rhGH therapy is superior to daily rhGH in children with GHD.

Physcion 8-O-ß-glucopyranoside exhibits anti-leukemic activity through targeting sphingolipid rheostat.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most common fatal cancer in people younger than 20 years of age. This study was designed to explore the anti-leukemia activity of physcion 8-O-ß-glucopyranoside (PG) in B-cell ALL. METHODS: NALM6 and SupB15 cells were used as model cell lines. Cell viability, cell apoptosis, cell cycle distribution were determined by CCK-8 assay, DNA fragmentation assay and flow cytometry, and flow cytometry, respectively. Expression of proteins involved in cell apoptosis and cell cycle regulation was determined by western blot and the levels of ceramide and sphingosine 1-phosphate (S1P) were determined by ELISA. Activity of sphingosine kinase 1 (SphK1) was also determined with a Sphingosine Kinase Assay Kit. In the present study, both model cell lines were transfected with siRNA targeting SphK1 or an overexpression plasmid to examine the role of SphK1 in the anti-leukemia activity of PG. Moreover, the efficacy of PG was examined in vivo in a mouse model by measuring survival and spleen weight. RESULTS: Our results provided experimental evidence that PG could significantly induce apoptosis and cell cycle arrest in vitro. Mechanistically, the anti-leukemia activity of PG was mediated by its ability to repress SphK1 and thus modulate ceramide-S1P rheostat. Moreover, the anti-leukemia activity of PG was also verified in a murine model. CONCLUSION: Collectively, our results indicate that PG may be a promising agent for the treatment of B-cell leukemia.

Cortisol promotes endoplasmic glucose production via pyridine nucleotide redox.

Both increased adrenal and peripheral cortisol production, the latter governed by 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), contribute to the maintenance of fasting blood glucose. In the endoplasmic reticulum (ER), the pyridine nucleotide redox state (NADP/NADPH) is dictated by the concentration of glucose-6-phosphate (G6P) and the coordinated activities of two enzymes, hexose-6-phosphate dehydrogenase (H6PDH) and 11ß-HSD1. However, luminal G6P may similarly serve as a substrate for hepatic glucose-6-phophatase (G6Pase). A tacit belief is that the G6P pool in the ER is equally accessible to both H6PDH and G6Pase. Based on our inhibition studies and kinetic analysis in isolated rat liver microsomes, these two aforesaid luminal enzymes do share the G6P pool in the ER, but not equally. Based on the kinetic modeling of G6P flux, the ER transporter for G6P (T1) preferentially delivers this substrate to G6Pase; hence, the luminal enzymes do not share G6P equally. Moreover, cortisol, acting through 11ß-HSD1, begets a more reduced pyridine redox ratio. By altering this luminal redox ratio, G6P flux through H6PDH is restrained, allowing more G6P for the competing enzyme G6Pase. And, at low G6P concentrations in the ER lumen, which occur during fasting, this acute cortisol-induced redox adjustment promotes glucose production. This reproducible cortisol-driven mechanism has been heretofore unrecognized.

Circulating microRNA profiles and the identification of miR-593 and miR-511 which directly target the PROP1 gene in children with combined pituitary hormone deficiency.

Since the tissue of children with combined pituitary hormone deficiency (CPHD) is not readily accessible, a new focus in children with CPHD is the blood-based expression profiling of non-protein coding genes, such as microRNAs (miRNAs or miRs), which regulate gene expression by inhibiting the translation of mRNAs. In this study, to address this, we identified potential miRNA signatures for CPHD by comparing genome-wide miRNA expression profiles in the serum of children with CPHD vs. normal (healthy) controls. Human embryonic kidney 293T cells were transfected with miR-593 or miR-511 oligonucleotides. Potential target gene expression was validated by western blot analysis for proteins and by miR-593 or miR-511 reporter assay using PROP1 gene 3'-untranslated region (3'-UTR) reporter. The miR-593 and miR-511 levels in the serum of 103 children with CPHD were assessed using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method. We found 23 upregulated and 19 downregulated miRNAs with abnormal expression in children with CPHD compared with the normal controls using miRNA microarray analysis and RT-qPCR. miR-593 and miR-511 targeted the 3'-UTR of the PROP1 gene and attenuated the expression of PROP1. The levels of miR-593 and miR-511 in the serum of children with CPHD were increased compared with those in the control subjects. According to Youden's index, the sensitivity was 82.54 and 84.86%, and the specificity was 98.15 and 91.36% for miR-593 and miR-511, respectively. The various levels of specific miRNAs, particularly miR-593 and miR-511 whose direct target is the PROP1 gene, may serve as a non-invasive diagnostic biomarkers for children with CPHD.