TMEM165 deficiency causes a congenital disorder of glycosylation.

Protein glycosylation is a complex process that depends not only on the activities of several enzymes and transporters but also on a subtle balance between vesicular Golgi trafficking, compartmental pH, and ion homeostasis. Through a combination of autozygosity mapping and expression analysis in two siblings with an abnormal serum-transferrin isoelectric focusing test (type 2) and a peculiar skeletal phenotype with epiphyseal, metaphyseal, and diaphyseal dysplasia, we identified TMEM165 (also named TPARL) as a gene involved in congenital disorders of glycosylation (CDG). The affected individuals are homozygous for a deep intronic splice mutation in TMEM165. In our cohort of unsolved CDG-II cases, we found another individual with the same mutation and two unrelated individuals with missense mutations in TMEM165. TMEM165 encodes a putative transmembrane 324 amino acid protein whose cellular functions are unknown. Using a siRNA strategy, we showed that TMEM165 deficiency causes Golgi glycosylation defects in HEK cells.

Efficacy and safety of the recombinant zoster vaccine: A systematic review and meta-analysis.

In this systematic review with meta-analysis, the efficacy, effectiveness, and safety of the new GSK recombinant zoster vaccine (RZV) were assessed.Twenty three publications reporting on 14 studies were selected, including 2 pivotal RCTs in older immunocompetent adults (ZOE-50 and ZOE-70), 4 RCTs on immunocompromised patients (haematopoietic stem cell transplantation (HSCT), haematological malignancies, solid tumour, and renal transplantation), and 8 observational studies. Vaccine efficacy of RZV against herpes zoster (HZ) and postherpetic neuralgia (PHN) was very high in immunocompetent older adults (respectively 94% and 91.2% in adults ≥50 years and 91.3% and 88.8% in adults ≥70 years). However, the number needed to vaccinate (NNV) was relatively high (between 32 and 36 for HZ and between 261 and 335 for PHN). Slow waning of the vaccine efficacy has been described after a median follow-up of 10 years after vaccination. In patients after HSCT, vaccine efficacy of RZV against HZ was lower compared to immunocompetent adults (68.2%), while vaccine efficacy of RZV against PHN was similar (89.3%). Higher incidences of HZ and PHN in patients after HSCT resulted in higher absolute reduction of cases and lower NNV (respectively 10 and 115). Observational studies confirmed a good vaccine effectiveness, albeit lower than in RCTs (ranging between 70% and 85%). No safety signal was identified neither in RCTs with immunocompetent or immunocompromised adults nor in observational studies and post-marketing surveillance. Increased reactogenicity after RZV vaccination, limited in extent and duration, did not result in low second dose compliance. Conclusion: Although vaccine efficacy in RCTs and effectiveness in the real world has been reported to be good, it needs to be stressed that high numbers of immunocompetent adults need to be vaccinated to prevent HZ and PHN. Due to higher incidence, more acceptable NNVs were calculated in immunocompromised adults after HSCT.

Chronotropic incompetence is more frequent in obese adolescents and relates to systemic inflammation and exercise intolerance.

BACKGROUND: Adults with obesity may display disturbed cardiac chronotropic responses during cardiopulmonary exercise testing, which relates to poor cardiometabolic health and an increased risk for adverse cardiovascular events. It is unknown whether cardiac chronotropic incompetence (CI) during maximal exercise is already present in obese adolescents and, if so, how that relates to cardiometabolic health. METHODS: Sixty-nine obese adolescents (body mass index standard deviation score = 2.23 ± 0.32, age = 14.1 ± 1.2 years; mean ± SD) and 29 lean adolescents (body mass index standard deviation score = -0.16 ± 0.84, age = 14.0 ± 1.5 years) performed a maximal cardiopulmonary exercise testing from which indicators for peak performance were determined. The resting heart rate and peak heart rate were used to calculate the maximal chronotropic response index. Biochemistry (lipid profile, glycemic control, inflammation, and leptin) was studied in fasted blood samples and during an oral glucose tolerance test within obese adolescents. Regression analyses were applied to examine associations between the presence of CI and blood or exercise capacity parameters, respectively, within obese adolescents. RESULTS: CI was prevalent in 32 out of 69 obese adolescents (46%) and 3 out of 29 lean adolescents (10%). C-reactive protein was significantly higher in obese adolescents with CI compared to obese adolescents without CI (p = 0.012). Furthermore, peak oxygen uptake and peak cycling power output were significantly reduced (p < 0.05) in obese adolescents with CI vs. obese adolescents without CI. The chronotropic index was independently related to blood total cholesterol (standardized coefficient ß = -0.332; p = 0.012) and C-reactive protein concentration (standardized coefficient ß = -0.269; p = 0.039). CONCLUSION: CI is more common in the current cohort of obese adolescents, and is related to systemic inflammation and exercise intolerance.

Cerebrocostomandibular-like syndrome and a mutation in the conserved oligomeric Golgi complex, subunit 1.

We describe two patients with a cerebrocostomandibular-like syndrome and a novel mutation in conserved oligomeric Golgi (COG) subunit 1, one of the subunits of the conserved oligomeric Golgi complex. This hetero-octameric protein complex is involved in retrograde vesicular trafficking and glycosylation. We identified in both patients an intronic mutation, c.1070+5G>A, that disrupts a splice donor site and leads to skipping of exon 6, a frameshift and a premature stopcodon in exon 7. Real-time reverse transcriptase polymerase chain reaction showed in the first patient only 3% of normal transcript when compared with control. A delay in retrograde trafficking could be demonstrated by Brefeldin A treatment of this patient's fibroblasts. The costovertebral dysplasia of the two patients has been described in cerebrocostomandibular syndrome (CCMS), but also in cerebrofaciothoracic dysplasia and spondylocostal dysostosis. CCMS itself is heterogeneous because both autosomal dominant and autosomal recessive inheritance has been described. We anticipate further genetic heterogeneity because no mutations in COG1 were found in two additional patients with a CCMS.

Comparison of flash glucose monitoring with real time continuous glucose monitoring in children and adolescents with type 1 diabetes treated with continuous subcutaneous insulin infusion.

AIMS: In 2016 intermittently scanned continuous glucose monitoring (isCGM) became the first reimbursed CGM system in Belgium. Many children with type 1 diabetes (T1D) treated with multiple daily injections as well as with continuous subcutaneous insulin infusion (CSII) switched from self-monitoring of blood glucose to isCGM to monitor their treatment. In 2017 the Enlite® real-time CGM (rtCGM) system was reimbursed enabling its use with the Minimed® 640G insulin pump with integrated SmartGuard technology. In this study we compared the metabolic control during CSII with isCGM with that during rtCGM. Patient's satisfaction and side effects of the rtCGM system were also evaluated. METHODS: 20 children with T1D, aged 5-16 years, were included. Metabolic control during the last month of isCGM use was compared to that during the 3rd and 6th month of rtCGM. RESULTS: Three patients stopped early rtCGM mainly due to calibration burden. The HbA1c level and the mean glucose value in the other patients did not change after switching to the rtCGM system. Glucose variability was smaller (46.2% vs 38.4% and 36.4%, p = 0.000). Time in hypoglycemia (<70 mg/dl) was lower (7.4% vs 1.6% and 1.5%, p = 0.000). The main patient inconvenience was the sensor calibration. CONCLUSIONS: Our data show that during Enlite® rtCGM with the Minimed® 640G pump system glucose variability was smaller and the patients spent less time in hypoglycemia than during isCGM. The need for timely calibrations is considered as the main drawback of the system.

Evaluation of the FreeStyle® Libre Flash Glucose Monitoring System in Children and Adolescents with Type 1 Diabetes.

BACKGROUND/AIMS: The FreeStyle® Libre Flash Glucose Monitoring System (FGM, Abbott) measures glucose concentrations in the interstitial fluid for up to 14 days. It has been approved for use in children aged > 4 years in January 2016. Experience in children is still limited. We evaluated the accuracy and usability of the FGM in children with type 1 diabetes mellitus (DM). METHODS: 67 children with type 1 DM (35 girls), aged 4-18 years, were included. Subjects wore a sensor on the back of their upper arm. For the first 14 days, they regularly measured capillary blood glucose (BG) with their usual BG meter (Accu-Chek® Mobile [ACM], Roche [n = 24]; Contour® Next Link [CNL], Bayer [n = 26]; OneTouch® Verio® IQ [OTV], LifeScan [n = 17]) followed by a sensor glucose (SG) scanning. SG readings were compared to BG measurements by consensus error grid (CEG) analysis; the mean difference (MD), the mean relative difference (MRD), the mean absolute difference (MAD), and the mean absolute relative difference (MARD) were calculated. After 14 days, subjects were asked to fill in a questionnaire on the usability of the FGM. RESULTS: 2,626 SG readings were paired with BG results. FGM readings were highly correlated with BG (r = 0.926, p < 0.001). 80.3% of the data pairs were in zone A (= no effect on clinical action) and 18.4% were in zone B (= altered clinical action with little or no effect on the clinical outcome) of the CEG. Overall MD was +7.5 mg/dL; MD varied with the BG meter: ACM +10.4 mg/dL, CNL +14.2 mg/dL, OTV -3.6 mg/dL (p < 0.001). Overall, MARD was 16.7%. We observed a large interindividual variability in the accuracy parameters. MD and MRD were inversely related to BMI (r = -0.261 [p < 0.05]; r = -0.266 [p < 0.05], respectively). MARD was inversely related to age (r = -0.266 [p < 0.05]). Twenty-nine patients (43.3%) reported sensor problems, mainly early detachment of the sensor. Nonetheless, the usability questionnaire indicated high levels of satisfaction. CONCLUSIONS: Our results showed a reasonable agreement between the FGM SG readings and capillary BG measurements in children. There was, however, a large interindividual variability. The wearing of the sensor requires special attention. Further studies in children are imperative in order to document the accuracy and safety of the FGM in the paediatric population.

A common mutation in the COG7 gene with a consistent phenotype including microcephaly, adducted thumbs, growth retardation, VSD and episodes of hyperthermia.

We describe the clinical and biochemical characteristics in three patients from two different families diagnosed with Congenital Disorder of Glycosylation type IIe owing to a defect in Conserved Oligomeric Golgi complex (COG)7; one of the eight subunits of the COG. The siblings and an unrelated single child of consanguineous parents presented with growth retardation, progressive, severe microcephaly, hypotonia, adducted thumbs, feeding problems by gastrointestinal pseudo-obstruction, failure to thrive, cardiac anomalies, wrinkled skin and episodes of extreme hyperthermia. A combined disorder in the biosynthesis of N- and O-linked glycosylation with hyposialylation was detected. Western blot analysis showed a severe reduction in the COG5 and 7 subunits of the COG. A homozygous, intronic splice site mutation (c.169+4A>C) of the COG7 gene was identified in all patients. The phenotype is similar to that previously described in two patients of North African ethnicity with the same mutation, except for the lack of skeletal anomalies and only a mild liver involvement in our patients. We suggest performing protein glycosylation studies and Western blot for the different COG subunits in patients with progressive microcephaly, growth retardation, hypotonia, adducted thumbs and cardiac defects, especially in association with skin anomalies or episodes of hyperthermia. The presence of the characteristic phenotype might warrant direct DNA analysis.

PGM1 deficiency diagnosed during an endocrine work-up of low IGF-1 mediated growth failure.

OBJECTIVE AND IMPORTANCE: Phosphoglucomutase 1 (PGM1) deficiency, first described as a glycogenosis (type XIV) is also a congenital disorder of glycosylation (CDG). We want to illustrate the wide clinical spectrum of PGM1 deficiency and in particular the associated disturbance in glucose metabolism and the endocrine dysfunction. Treatment with d-galactose is experimental. CASE PRESENTATION: PGM1 deficiency was diagnosed in an 8-year-old boy, who was referred because of an unexplained complex syndrome, including recurrent hypoglycaemia and low IGF-1 mediated growth failure. CONCLUSION: The timely diagnosis of this disorder is particularly important, because d-galactose treatment can improve the latter symptoms.

A novel mutation causing mild, atypical fumarylacetoacetase deficiency (Tyrosinemia type I): a case report.

A male patient, born to unrelated Belgian parents, presented at 4 months with epistaxis, haematemesis and haematochezia. On physical examination he presented petechiae and haematomas, and a slightly enlarged liver. Serum transaminases were elevated to 5-10 times upper limit of normal, alkaline phosphatases were 1685 U/L (<720), total bilirubin was 2.53 mg/dl (<1.0), ammonaemia 69 microM (<32), prothrombin time less than 10%, thromboplastin time >180 s (<60) and alpha-fetoprotein 29723 microg/L (<186). Plasma tyrosine (651 microM) and methionine (1032 microM) were strongly increased. In urine, tyrosine metabolites and 4-oxo-6-hydroxyheptanoic acid were increased, but succinylacetone and succinylacetoacetate--pathognomonic for tyrosinemia type I--were repeatedly undetectable. Delta-aminolevulinic acid was normal, which is consistent with the absence of succinylacetone. Abdominal ultrasound and brain CT were normal.Fumarylacetoacetase (FAH) protein and activity in cultured fibroblasts and liver tissue were decreased but not absent. 4-hydroxyphenylpyruvate dioxygenase activity in liver was normal, which is atypical for tyrosinemia type I. A novel mutation was found in the FAH gene: c.103G>A (Ala35Thr). In vitro expression studies showed this mutation results in a strongly decreased FAH protein expression.Dietary treatment with phenylalanine and tyrosine restriction was initiated at 4 months, leading to complete clinical and biochemical normalisation. The patient, currently aged 12 years, shows a normal physical and psychomotor development.This is the first report of mild tyrosinemia type I disease caused by an Ala35Thr mutation in the FAH gene, presenting atypically without increase of the diagnostically important toxic metabolites succinylacetone and succinylacetoacetate.

A new mutation in COG7 extends the spectrum of COG subunit deficiencies.

We describe a patient homozygous for a novel mutation in COG7, coding for one of the subunits of the Conserved Oligomeric Golgi complex, involved in retrograde vesicular trafficking. His brother showed a similar clinical syndrome and glycosylation defect but no DNA could be obtained from this patient. This mutation, c.170-7A > G, activates a cryptic splice acceptor and leads to the insertion of 2 amino acids at protein level (p.56-57insAT). The insertion disturbs the structure and function of the Conserved Oligomeric Golgi complex. In comparison to the previously described patients with a different COG7 mutation, intrauterine growth retardation and dysmorphic features were absent and there was a longer survival.

Identification of a novel PEX14 mutation in Zellweger syndrome.

Here we report a patient with Zellweger syndrome, who presented at the age of 3 months with icterus, dystrophy, axial hypotonia, and hepatomegaly. Abnormal findings of metabolic screening tests included hyperbilirubinaemia, hypoketotic dicarboxylic aciduria, increased C(26:0) and decreased C(22:0) plasma levels, and strongly reduced plasmalogen concentrations. In fibroblasts, both peroxisomal α- and ß-oxidation were impaired. Liver histology revealed bile duct paucity, cholestasis, arterial hyperplasia, very small branches of the vena portae, and parenchymatic destruction. Immunocytochemical analysis of cultured fibroblasts demonstrated that the cells contain peroxisomal remnants lacking apparent matrix protein content and PEX14, a central membrane component of the peroxisomal matrix protein import machinery. Transfection of fibroblasts with a plasmid coding for wild-type PEX14 restored peroxisomal matrix protein import. Mutational analysis of this gene revealed a genomic deletion leading to the deletion of exon 3 from the coding DNA (c.85-?_170+?del) and a concomitant change of the reading frame (p.[Ile29_Lys56del;Gly57GlyfsX2]).

Deficiencies in subunits of the Conserved Oligomeric Golgi (COG) complex define a novel group of Congenital Disorders of Glycosylation.

Processing of the glycan structures on glycoproteins by different glycosylation enzymes depends on, among other, the non-uniform distribution of these enzymes within the Golgi stacks. This compartmentalization is achieved by a balance between anterograde and retrograde vesicular trafficking. If the balance is disturbed, the glycosylation machinery is mislocalized, which can cause Congenital Disorders of Glycosylation type II (CDG-II), as illustrated by the identification of congenital defects in the Conserved Oligomeric Golgi (COG) complex in humans. We collected findings from different COG deficient cell types, such as CHO, yeast and human fibroblasts to hypothesize about structure and function of the COG complex, and compared the phenotypes and genotypes of the patients known with a COG deficiency. Among 35 CDG-II patients we found 5 patients with a COG defect. COG defects are a novel group of CDG-II with deficient N- as well as O-glycosylation.

A new inborn error of glycosylation due to a Cog8 deficiency reveals a critical role for the Cog1-Cog8 interaction in COG complex formation.

The hetero-octameric conserved oligomeric Golgi (COG) complex is essential for the structure/function of the Golgi apparatus through regulation of membrane trafficking. Here, we describe a patient with a mild form of a congenital disorder of glycosylation type II (CDG-II), which is caused by a homozygous nonsense mutation in the hCOG8 gene. This leads to a premature stop codon resulting in a truncated Cog8 subunit lacking the 76 C-terminal amino acids. Mass spectrometric analysis of the N- and O-glycan structures identified a mild sialylation deficiency. We showed that the molecular basis of this defect in N- and O-glycosylation is caused by the disruption of the Cog1-Cog8 interaction due to truncation. As a result, Cog1 deficiency accompanies the Cog8 deficiency, preventing assembly of the intact, stable complex and resulting in the appearance of smaller subcomplexes. Moreover, levels of beta1,4-galactosytransferase were significantly reduced. The defects in O-glycosylation could be fully restored by transfecting the patient's fibroblasts with full-length Cog8. The Cog8 defect described here represents a novel type of CDG-II, which we propose to name as CDG-IIh or CDG caused by Cog8 deficiency (CDG-II/Cog8).