Fasting and non-fasting plasma levels of monomethyl branched chain fatty acids: Implications for maple syrup urine disease.

The branched-chain amino acids (BCAA) leucine, valine, and isoleucine provide precursors for monomethyl branched-chain fatty acids (BCFA). Established reference ranges for BCFAs are lacking. In maple syrup urine disease (MSUD), a rare inborn error of BCAA metabolism, the endogen production is impaired and MSUD patients are treated with a low protein (low BCAA) diet. The protein restriction may affect the dietary intake of BCFA, depending on the dietary choices made. Patients with MSUD are prescribed a more or less protein-restricted diet depending on the severity of the disease. The combination of a protein-restricted diet and subsequent impaired endogenous synthesis may render MSUD patients sensitive to BCFA deficiency, with yet unknown implications. To investigate the possibility of lower circulatory BCFA levels in MSUD that favors dietary BCFA supplementation, we first established fasting-state reference ranges for selected BCFAs and saturated/unsaturated fatty acids in plasma. Then, the effect of fasting on BCFA levels was evaluated by comparing the distribution in a fasting versus a non-fasting cohort. To test the hypothesis that BCFA deficiency could contribute to MSUD pathophysiology, we recruited patients with intermittent, intermediate, and classical form of MSUD and analyzed the corresponding BCFA z-scores. None of the BCFA species had |z-scores| > 2 relative to the reference range. Our findings do not support the requirement of BCFA supplementation in MSUD patients. The origin of BCFAs is discussed. Impaired capacity to synthesize BCFA do not manifest as reduced plasma levels in MSUD, suggesting that endogenous synthesis is dispensable for plasma levels.

Renal function, sex and age influence purines and pyrimidines in urine and could lead to diagnostic misinterpretation.

Glomerular filtration rate (GFR) is commonly used in clinical practice for the diagnosis and follow-up of chronic kidney disease. Screening for inborn errors of metabolism (IEM) is based on analysis of biomarkers in urine, reported by their ratio to urinary creatinine (crn). Impaired renal function may complicate the interpretation of several biomarkers used for screening of IEM. Our goal was to investigate the influence of kidney function, in terms of measured GFR (mGFR) on purines and pyrimidines in urine, in addition to the relationship to sex, age, pH and ketosis. Children (n = 96) with chronic kidney disease (CKD), in different CKD stages, were included. Urine samples were obtained prior to the injection of iohexol. Serum samples at 7 time-points were used to calculate mGFR based on iohexol plasma clearance. The association with sex, age, ketosis and pH was examined in samples of the laboratory production from 2015 to 2021 (n = 8192). Age was a highly significant covariate for all markers. GFR correlated positively to several purines and pyrimidines; the ratios hypoxanthine/crn, xanthine/crn and urate/crn (p = 2.0 × 10-14, < 3 × 10-15 and 7.2 × 10-4, respectively), and the ratios orotic acid/crn, uracil/crn, and carbamyl-ß-alanine/crn (p = 0.03, 1.4 × 10-6 and 0.003, respectively). The values of urate/crn, xanthine/crn, uracil/crn, and carbamyl-ß-alanine/crn were higher in females above 16 years of age. Ketosis and pH influenced some markers. In conclusion, decreased renal function interferes with the excretion of urinary purines and pyrimidines, and this could change decision limits substantially, e.g. result in false negative results in Lesch-Nyhan syndrome. SYNOPSIS: GFR influences purines and pyrimidines in urine. Clinical Trial Registration: ClinicalTrials.gov, Identifier NCT01092260, https://clinicaltrials.gov/ct2/show/NCT01092260?term=tondel&rank=2.

BCKDK deficiency: a treatable neurodevelopmental disease amenable to newborn screening.

There are few causes of treatable neurodevelopmental diseases described to date. Branched-chain ketoacid dehydrogenase kinase (BCKDK) deficiency causes branched-chain amino acid (BCAA) depletion and is linked to a neurodevelopmental disorder characterized by autism, intellectual disability and microcephaly. We report the largest cohort of patients studied, broadening the phenotypic and genotypic spectrum. Moreover, this is the first study to present newborn screening findings and mid-term clinical outcome. In this cross-sectional study, patients with a diagnosis of BCKDK deficiency were recruited via investigators' practices through a MetabERN initiative. Clinical, biochemical and genetic data were collected. Dried blood spot (DBS) newborn screening (NBS) amino acid profiles were retrieved from collaborating centres and compared to a healthy newborn reference population. Twenty-one patients with BCKDK mutations were included from 13 families. Patients were diagnosed between 8 months and 16 years (mean: 5.8 years, 43% female). At diagnosis, BCAA levels (leucine, valine and isoleucine) were below reference values in plasma and in CSF. All patients had global neurodevelopmental delay; 18/21 had gross motor function (GMF) impairment with GMF III or worse in 5/18, 16/16 intellectual disability, 17/17 language impairment, 12/17 autism spectrum disorder, 9/21 epilepsy, 12/15 clumsiness, 3/21 had sensorineural hearing loss and 4/20 feeding difficulties. No microcephaly was observed at birth, but 17/20 developed microcephaly during follow-up. Regression was reported in six patients. Movement disorder was observed in 3/21 patients: hyperkinetic movements (1), truncal ataxia (1) and dystonia (2). After treatment with a high-protein diet (≥ 2 g/kg/day) and BCAA supplementation (100-250 mg/kg/day), plasma BCAA increased significantly (P < 0.001), motor functions and head circumference stabilized/improved in 13/13 and in 11/15 patients, respectively. Among cases with follow-up data, none of the three patients starting treatment before 2 years of age developed autism at follow-up. The patient with the earliest age of treatment initiation (8 months) showed normal development at 3 years of age. NBS in DBS identified BCAA levels significantly lower than those of the normal population. This work highlights the potential benefits of dietetic treatment, in particular early introduction of BCAA. Therefore, it is of utmost importance to increase awareness about this treatable disease and consider it as a candidate for early detection by NBS programmes.

Clinical Variables as Indicative Factors for Endoscopy in Adolescents with Esophageal Atresia.

INTRODUCTION: Gastro-esophageal reflux disease (GERD) occurs frequently in patients operated for esophageal atresia (EA). Longstanding esophagitis may lead to dysphagia, strictures, columnar metaplasia, and dysplasia with an increased risk of adenocarcinoma. Are clinical factors and non-invasive assessments reliable indicators for follow-up with endoscopy? MATERIAL AND METHOD: A follow-up study with inclusion of EA adolescents in Norway born between 1996 and 2002 was conducted. Clinical assessment with pH monitoring, endoscopy with biopsies, along with interviews and questionnaires regarding gastroesophageal reflux disease (GERD) and dysphagia were performed. RESULTS: We examined 68 EA adolescents. 62% reported GERD by interview, 22% by questionnaire. 85% reported dysphagia by interview, 71% by questionnaire. 24-hour pH monitoring detected pathological reflux index (RI) (>7%) in 7/59 (12%). By endoscopy with biopsy 62 (92%) had histologic esophagitis, of whom 3 (4%) had severe esophagitis. Gastric metaplasia was diagnosed in twelve (18%) adolescents, intestinal metaplasia in only one (1.5%). None had dysplasia or carcinoma. Dysphagia and GERD were statistically correlated to esophagitis and metaplasia, but none of the questionnaires or interviews alone were good screening instruments with high combined sensitivity and specificity. A compound variable made by simply taking the mean of rescaled RI and dysphagia by interview showed to be the best predictor of metaplasia (85% sensitivity, 67% specificity). CONCLUSION: The questionnaires and interviews used in the present study were not good screening instruments alone. However, combining dysphagia score by interview and RI may be helpful in assessing which patients need endoscopy with biopsy at each individual follow-up examination. LEVEL OF EVIDENCE: Level II prognostic study.

New insights in the prevalence of scoliosis and musculoskeletal asymmetries in adolescents with esophageal atresia.

BACKGROUND: Increased risk of scoliosis and musculoskeletal abnormalities in adolescents with esophageal atresia (EA) is reported, but the impact of these abnormalities on physical fitness and motor skills are not known. METHODS: Scoliosis was assessed radiographically and shoulder and chest abnormalities by a standardized protocol. Physical fitness was evaluated with Grippit, Six-minute walk test, and International Physical Activity Questionnaire and motor skills by Motor Assessment Battery for Children. RESULTS: Sixty-seven EA adolescents median 16 (13-20) years participated. The prevalence of significant scoliosis (≥ 20º) was 12% (8/67) whereas 22% (15/67) had mild scoliosis (10-19º). Vertebral anomalies occurred in 18/67 (27%), eight of them (44%) had scoliosis. The majority of adolescents (15/23) with scoliosis did not have vertebral anomalies. Musculoskeletal abnormalities were detected in 22-78%. Balance problems occurred three times more frequently than expected (44% vs. 15%, p = 0.004). Submaximal exercise capacity was significantly reduced compared to reference values (p < 0.001). Scoliosis ≥ 20º was related to reduced physical activity (p = 0.008), and musculoskeletal abnormalities to reduced physical activity and impaired motor skills (p = 0.042 and p < 0.038, respectively). CONCLUSIONS: Significant scoliosis was diagnosed in 12% of the EA adolescents and related to reduced physical activity. Musculoskeletal abnormalities identified in more than half of the patients, were related to reduced physical activity and impaired motor skills, and exercise capacity was significantly below reference group. EA patients with and without vertebral anomalies need health-promoting guidance to prevent impaired motor skills and consequences of reduced physical activity. LEVEL OF EVIDENCE: Prognostic Study, Level II.

Bloodlettings in Hemochromatosis Result in Increased Blood Lead (Pb) Concentrations.

Hemochromatosis is a hereditary disorder, most often associated with mutations of the HFE (High FErrum) gene. If left untreated, it can result in severe parenchymal iron accumulation. Bloodletting is the mainstay treatment. We have previously shown that treatment of hemochromatosis by repeated bloodlettings may induce changes in the serum levels of several trace elements. The aim of this work was to evaluate if whole blood concentrations of the environmental pollutants lead (Pb), mercury (Hg), and cadmium (Cd) could be affected by bloodlettings. We recruited 28 patients and 21 healthy individuals (control group). Whole blood and urine levels of Pb, Hg, and Cd were measured before the start and after the completion of treatment using inductively coupled plasma mass spectrometry, together with serum iron and liver function tests. Concentrations of blood Pb, but not Hg or Cd, were significantly increased after treatment. The increase in Pb was higher in C282Y homozygous patients than in the other patients, and it was positively correlated with the serum concentration of alkaline phosphatase. Bloodlettings in hemochromatosis result in an increase in the blood concentration of Pb. Augmented absorption due to iron loss or Pb mobilization from bone may contribute to the higher blood Pb level.

Breastfed Infants With Spells, Tremor, or Irritability: Rule Out Vitamin B12 Deficiency.

BACKGROUND: In Norway, 5-10% of neonates and infants have biomarkers suggesting vitamin B12 deficiency from newborn screening tests and unselected clinical screening, respectively. AIMS: The aims were to identify risk factors and describe presenting symptoms and biochemical profiles in infants diagnosed with vitamin B12 deficiency. METHODS: In this case-control study, we searched hospital medical records for infants younger than one year born in 2011-2018, diagnosed with vitamin B12 deficiency. We compared 85 cases with a control group of 252 infants aged 3-7 months. Parents completed questionnaires. RESULTS: Of the 85 cases with vitamin B12 deficiency, 80% presented with spells (37%) of apneas, motor seizures, or absences within the first two months of life. Tremor (29%) and irritability (18%) were the most common findings at the first examination. Serum total homocysteine ≥10 µmol/L was found in 77% of cases compared to 28% of controls (P < 0.001). None of the mothers were vegetarians, but 25% reported a previous history of vitamin B12 deficiency and 7% had celiac disease. The dose of nitrous oxide given during labor was significantly associated with infant serum total homocysteine level at diagnosis (r = 0.37, 95% confidence interval = 0.16-0.55, P < 0.001) for cases, but not for controls. CONCLUSION: Spells, tremor, and irritability are common findings in early infant vitamin B12 deficiency. Nitrous oxide given during labor is proposed as a contributing risk factor to the development of early infant vitamin B12 deficiency.

High Plasma Oxalate Levels Early After Kidney Transplantation Are Associated With Impaired Long-Term Outcomes.

Background: Elevated levels of oxalate are common in renal failure patients and non-hyperoxaluria disease, and may cause damage after transplantation. We examined outcomes after 15 years for 167 kidney transplant recipients who had plasma oxalate measured early after transplantation. Analyses included plasma oxalate, recipient age, donor age, live donor, HLA-DR mismatch, mGFR, and smoking. Results: Median age was 52 years (range 18-81), 63% were male and 38% had live donors. Median plasma oxalate concentration 10 weeks after transplantation was 9.0 µmol/L (range 2.7-53.0), one third above the upper reference limit (11.0 µmol/L). Multivariable analysis revealed upper quartile plasma oxalate (>13.0 µmol/L, p = 0.008), recipient age (p < 0.001), deceased donor (p = 0.003), and current smoking (p < 0.001) as significant factors associated with patient survival. Upper quartile plasma oxalate (p = 0.021), recipient age (p = 0.001), deceased donor kidney (p = 0.001), HLA-DR mismatch (p = 0.015), and current smoking (p = 0.014) were also associated with graft loss. Factors associated with death censored graft losses were donor age (p = 0.012), deceased donor (p = 0.032), and HLA-DR mis-matched kidneys (p = 0.005) but plasma oxalate was not (p = 0.188). Conclusions: Plasma oxalate in the upper quartile early after transplantation was significantly associated with impaired long-term patient survival and graft losses, but not when censored for death.

ZBTB11 dysfunction: spectrum of brain abnormalities, biochemical signature and cellular consequences.

Bi-allelic pathogenic variants in ZBTB11 have been associated with intellectual developmental disorder, autosomal recessive 69 (MRT69; OMIM 618383). We report five patients from three families with novel, bi-allelic variants in ZBTB11. We have expanded the clinical phenotype of MRT69, documenting varied severity of atrophy affecting different brain regions and described combined malonic and methylmalonic aciduria as a biochemical manifestation. As ZBTB11 encodes for a transcriptional regulator, we performeded chromatin immunoprecipitation-sequencing targeting ZBTB11 in fibroblasts from patients and controls. Chromatin immunoprecipitation-sequencing revealed binding of wild-type ZBTB11 to promoters in 238 genes, among which genes encoding proteins involved in mitochondrial functions and RNA processing are over-represented. Mutated ZBTB11 showed reduced binding to 61 of the targeted genes, indicating that the variants act as loss of function. Most of these genes are related to mitochondrial functions. Transcriptome analysis of the patient fibroblasts revealed dysregulation of mitochondrial functions. In addition, we uncovered that reduced binding of the mutated ZBTB11 to ACSF3 leads to decreased ACSF3 transcript level, explaining combined malonic and methylmalonic aciduria. Collectively, these results expand the clinical spectrum of ZBTB11-related neurological disease and give insight into the pathophysiology in which the dysfunctional ZBTB11 affect mitochondrial functions and RNA processing contributing to the neurological and biochemical phenotypes.

Prevalence of antibodies against SARS-CoV-2 among pregnant women in Norway during the period December 2019 through December 2020.

We studied severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence among pregnant women in Norway by including all women who were first trimester pregnant (n = 6520), each month from December 2019 through December 2020, in the catchment region of Norway's second-largest hospital. We used sera that had been frozen stored after compulsory testing for syphilis antibodies in antenatal care. The sera were analysed with the Elecsys® Anti-SARS-CoV-2 immunoassay (Roche Diagnostics, Cobas e801). This immunoassay detects IgG/IgM against SARS-CoV-2 nucleocapsid antigen. Sera with equivocal or positive test results were retested with the Liaison® SARS-CoV-2 S1/S2 IgG (DiaSorin), which detects IgG against the spike (S)1 and S2 protein on the SARS-CoV-2 virus. In total, 98 women (adjusted prevalence 1.7%) had SARS CoV-2 antibodies. The adjusted seroprevalence increased from 0.3% (1/445) in December 2019 to 5.7% (21/418) in December 2020. Out of the 98 seropositive women, 36 (36.7%) had serological signs of current SARS-CoV-2 infection at the time of serum sampling, and the incidence remained low during the study period. This study suggests that SARS CoV-2 was present in the first half of December 2019, 6 weeks before the first case was recognised in Norway. The low occurrence of SARS-CoV-2 infection during 2020, may be explained by high compliance to extensive preventive measures implemented early in the epidemic.

The prevalence and clinical relevance of hyperhomocysteinemia suggesting vitamin B12 deficiency in presumed healthy infants.

BACKGROUND: Previous studies have demonstrated a high prevalence of biochemical vitamin B12 deficiency in infants in Norway. Increased total homocysteine (tHcy) is the most important marker of B12 deficiency in infants. There is a need to evaluate its clinical relevance. AIMS: To investigate the prevalence of hyperhomocysteinemia (S-tHcy > 8 µmol/L) suggestive of suboptimal B12 status and the prevalence of clinically relevant hyperhomocysteinemia in presumed healthy infants in Norway. Further, to evaluate risk factors, presence of symptoms and psychomotor development in these children. METHODS: In a prospective study we clinically examined 252 infants aged 3-7 months using standardized neurological and psychomotor tests prior to analyzing biochemical B12 deficiency markers in 250 infants. RESULTS: Twenty-five of 250 (10%) infants had hyperhomocysteinemia combined with clinically relevant symptoms suggestive of B12 deficiency. Hyperhomocysteinemia was associated with tremor, excessive sleep, and sub-normal scores in the fine motor section of the Ages and Stages Questionnaire. One-hundred and fourteen of 250 (46%) infants had hyperhomocysteinemia. Multiple regression analysis showed months of infant formula use as the strongest negative predictor for hyperhomocysteinemia. CONCLUSION: We have demonstrated associations between symptoms suggestive of infant B12 deficiency and increased levels of tHcy in presumed healthy infants The combination of hyperhomocysteinemia and associated relevant symptoms suggestive of B12 deficiency was a common finding, albeit most infants with hyperhomocysteinemia did not show symptoms.

A Novel Approach to Improve Newborn Screening for Congenital Hypothyroidism by Integrating Covariate-Adjusted Results of Different Tests into CLIR Customized Interpretive Tools.

Newborn screening for congenital hypothyroidism remains challenging decades after broad implementation worldwide. Testing protocols are not uniform in terms of targets (TSH and/or T4) and protocols (parallel vs. sequential testing; one or two specimen collection times), and specificity (with or without collection of a second specimen) is overall poor. The purpose of this retrospective study is to investigate the potential impact of multivariate pattern recognition software (CLIR) to improve the post-analytical interpretation of screening results. Seven programs contributed reference data (N = 1,970,536) and two sets of true (TP, N = 1369 combined) and false (FP, N = 15,201) positive cases for validation and verification purposes, respectively. Data were adjusted for age at collection, birth weight, and location using polynomial regression models of the fifth degree to create three-dimensional regression surfaces. Customized Single Condition Tools and Dual Scatter Plots were created using CLIR to optimize the differential diagnosis between TP and FP cases in the validation set. Verification testing correctly identified 446/454 (98%) of the TP cases, and could have prevented 1931/5447 (35%) of the FP cases, with variable impact among locations (range 4% to 50%). CLIR tools either as made here or preferably standardized to the recommended uniform screening panel could improve performance of newborn screening for congenital hypothyroidism.

Higher blood pressure in normal weight women with PCOS compared to controls.

OBJECTIVE: Obesity is considered to be the strongest predictive factor for cardio-metabolic risk in women with polycystic ovary syndrome (PCOS). The aim of the study was to compare blood pressure (BP) in normal weight women with PCOS and controls matched for age and BMI. METHODS: From a Nordic cross-sectional base of 2615 individuals of Nordic ethnicity, we studied a sub cohort of 793 normal weight women with BMI < 25 kg/m2 (512 women with PCOS according to Rotterdam criteria and 281 age and BMI-matched controls). Participants underwent measurement of BP and body composition (BMI, waist-hip ratio), lipid status, and fasting BG. Data were presented as median (quartiles). RESULTS: The median age for women with PCOS were 28 (25, 32) years and median BMI was 22.2 (20.7, 23.4) kg/m2. Systolic BP was 118 (109, 128) mmHg in women with PCOS compared to 110 (105, 120) mmHg in controls and diastolic BP was 74 (67, 81) vs 70 (64, 75) mmHg, both P < 0.001. The prevalence of women with BP ≥ 140/90 mmHg was 11.1% (57/512) in women with PCOS vs 1.8% (5/281) in controls, P < 0.001. In women ≥ 35 years the prevalence of BP ≥ 140/90 mmHg was comparable in women with PCOS and controls (12.7% vs 9.8%, P = 0.6). Using multiple regression analyses, the strongest association with BP was found for age, waist circumference, and total cholesterol in women with PCOS. CONCLUSIONS: Normal weight women with PCOS have higher BP than controls. BP and metabolic screening are relevant also in young normal weight women with PCOS.

Impaired motor performance in adolescents with esophageal atresia.

AIMS: The study prospectively assessed motor development from infancy to adolescence in patients with esophageal atresia (EA). METHODS: At one year of age motor performance was evaluated with the Psychomotor Developmental Index (PDI) of the Bayley Scales of Infant Development, Second Edition (BSID-II), and as adolescents reevaluated with Motor Assessment Battery for Children, Second Edition (MABC-2). Associations to clinical factors were assessed. RESULTS: 23 EA patients were followed from infancy to adolescence. The median total PDI score in infancy was 102 (56-118) and the corresponding mean z-score was -0.006 (SD 0.995) and not significantly different from the reference values (p = 0.48). The median total MABC-2 score in adolescence was 75 (32-93) and the corresponding mean z-score -0.43 (SD 0.998) which is significantly below normal (p = 0.03). Children with impaired motor function in adolescence underwent significantly more rethoracotomies than those with normal motor performance (p = 0.037); whereas the two groups did not differ with respect to other clinical characteristics. CONCLUSION: From infancy to adolescence the motor performance in the group of EA patients deteriorated from within normal range to significantly impaired compared to reference values. Interdisciplinary follow-up programs from infancy to adolescence with close monitoring for motor function is necessary to detect motor impairments.

Phosphoglucomutase-1 deficiency: Early presentation, metabolic management and detection in neonatal blood spots.

Phosphoglucomutase 1 deficiency is a congenital disorder of glycosylation (CDG) with multiorgan involvement affecting carbohydrate metabolism, N-glycosylation and energy production. The metabolic management consists of dietary D-galactose supplementation that ameliorates hypoglycemia, hepatic dysfunction, endocrine anomalies and growth delay. Previous studies suggest that D-galactose administration in juvenile patients leads to more significant and long-lasting effects, stressing the urge of neonatal diagnosis (0-6 months of age). Here, we detail the early clinical presentation of PGM1-CDG in eleven infantile patients, and applied the modified Beutler test for screening of PGM1-CDG in neonatal dried blood spots (DBSs). All eleven infants presented episodic hypoglycemia and elevated transaminases, along with cleft palate and growth delay (10/11), muscle involvement (8/11), neurologic involvement (5/11), cardiac defects (2/11). Standard dietary measures for suspected lactose intolerance in four patients prior to diagnosis led to worsening of hypoglycemia, hepatic failure and recurrent diarrhea, which resolved upon D-galactose supplementation. To investigate possible differences in early vs. late clinical presentation, we performed the first systematic literature review for PGM1-CDG, which highlighted respiratory and gastrointestinal symptoms as significantly more diagnosed in neonatal age. The modified Butler-test successfully identified PGM1-CDG in DBSs from seven patients, including for the first time Guthrie cards from newborn screening, confirming the possibility of future inclusion of PGM1-CDG in neonatal screening programs. In conclusion, severe infantile morbidity of PGM1-CDG due to delayed diagnosis could be prevented by raising awareness on its early presentation and by inclusion in newborn screening programs, enabling early treatments and galactose-based metabolic management.

Second-Tier Next Generation Sequencing Integrated in Nationwide Newborn Screening Provides Rapid Molecular Diagnostics of Severe Combined Immunodeficiency.

Severe combined immunodeficiency (SCID) and other T cell lymphopenias can be detected during newborn screening (NBS) by measuring T cell receptor excision circles (TRECs) in dried blood spot (DBS) DNA. Second tier next generation sequencing (NGS) with an amplicon based targeted gene panel using the same DBS DNA was introduced as part of our prospective pilot research project in 2015. With written parental consent, 21 000 newborns were TREC-tested in the pilot. Three newborns were identified with SCID, and disease-causing variants in IL2RG, RAG2, and RMRP were confirmed by NGS on the initial DBS DNA. The molecular findings directed follow-up and therapy: the IL2RG-SCID underwent early hematopoietic stem cell transplantation (HSCT) without any complications; the leaky RAG2-SCID received prophylactic antibiotics, antifungals, and immunoglobulin infusions, and underwent HSCT at 1 year of age. The child with RMRP-SCID had complete Hirschsprung disease and died at 1 month of age. Since January 2018, all newborns in Norway have been offered NBS for SCID using 1st tier TRECs and 2nd tier gene panel NGS on DBS DNA. During the first 20 months of nationwide SCID screening an additional 88 000 newborns were TREC tested, and four new SCID cases were identified. Disease-causing variants in DCLRE1C, JAK3, NBN, and IL2RG were molecularly confirmed on day 8, 15, 8 and 6, respectively after birth, using the initial NBS blood spot. Targeted gene panel NGS integrated into the NBS algorithm rapidly delineated the specific molecular diagnoses and provided information useful for management, targeted therapy and follow-up i.e., X rays and CT scans were avoided in the radiosensitive SCID. Second tier targeted NGS on the same DBS DNA as the TREC test provided instant confirmation or exclusion of SCID, and made it possible to use a less stringent TREC cut-off value. This allowed for the detection of leaky SCIDs, and simultaneously reduced the number of control samples, recalls and false positives. Mothers were instructed to stop breastfeeding until maternal cytomegalovirus (CMV) status was determined. Our limited data suggest that shorter time-interval from birth to intervention, may prevent breast milk transmitted CMV infection in classical SCID.

Higher vitamin B12 levels in neurodevelopmental disorders than in healthy controls and schizophrenia: A comparison among participants between 2 and 53 years.

Recent studies suggest that both high and low levels of vitamin B12 (vitB12) may have negative health impacts. We measured VitB12 in patients with the Neurodevelopmental disorders (ND) (n = 222), comprised of Autism Spectrum Disorders, specific Developmental disorders, and Intellectual Disability (aged 2-53 years), schizophrenia (n = 401), and healthy controls (HC) (n = 483). Age-and gender-adjusted vitB12 z-scores were calculated by comparisons with a reference population (n = 76 148). We found higher vitB12 in ND (median 420 pmol/L, mean z-score: 0.30) than in HC (316 pmol/L, z-score: 0.06, P < .01) and schizophrenia (306 pmol/L, z-score: -0.02, P < .001), which was significant after adjusting for age, gender, vitB12 supplement, folate, hemoglobin, leukocytes, liver, and kidney function (P < .02). In ND, 20% (n = 44) had vitB12 above 650 pmol/L, and 1% (n = 3) had below 150 pmol/L (common reference limits). In 6.3% (n = 14) of ND, vitB12 was above 2SD of mean in the age-and gender-adjusted reference population, which was more frequent than in HC (n = 8, 1.6%), OR: 4.0, P = .001. Low vitB12 was equally frequent as in HC, and vitB12 z-scores were equal across the age groups. To conclude, vitB12 was higher in ND than in HC and schizophrenia, suggesting a specific feature of ND, which warrants further studies to investigate the underlying mechanisms.

Structural basis for substrate and product recognition in human phosphoglucomutase-1 (PGM1) isoform 2, a member of the α-D-phosphohexomutase superfamily.

Human phosphoglucomutase 1 (PGM1) is an evolutionary conserved enzyme that belongs to the ubiquitous and ancient α-D-phosphohexomutases, a large enzyme superfamily with members in all three domains of life. PGM1 catalyzes the bi-directional interconversion between α-D-glucose 1-phosphate (G1P) and α-D-glucose 6-phosphate (G6P), a reaction that is essential for normal carbohydrate metabolism and also important in the cytoplasmic biosynthesis of nucleotide sugars needed for glycan biosynthesis. Clinical studies have shown that mutations in the PGM1 gene may cause PGM1 deficiency, an inborn error of metabolism previously classified as a glycogen storage disease, and PGM1 deficiency was recently also shown to be a congenital disorder of glycosylation. Here we present three crystal structures of the isoform 2 variant of PGM1, both as a free enzyme and in complex with its substrate and product. The structures show the longer N-terminal of this PGM1 variant, and the ligand complex structures reveal for the first time the detailed structural basis for both G1P substrate and G6P product recognition by human PGM1. We also show that PGM1 and the paralogous gene PGM5 are the results of a gene duplication event in a common ancestor of jawed vertebrates, and, importantly, that both PGM1 isoforms are conserved and of functional significance in all vertebrates. Our finding that PGM1 encodes two equally conserved and functionally important isoforms in the human organism should be taken into account in the evaluation of disease-related missense mutations in patients in the future.

Mechanical dispersion as a marker of left ventricular dysfunction and prognosis in stable coronary artery disease.

Assessment of global longitudinal strain (GLS) is superior to ejection fraction (EF) in the evaluation of left ventricular (LV) function in patients with stable coronary artery disease (CAD). However, the role of mechanical dispersion (MD) in this context remains unresolved. We aimed to evaluate the potential role of MD as a marker of LV dysfunction and long-term prognosis in stable CAD. EF, GLS and MD were assessed in 160 patients with stable CAD, 1 year after successful coronary revascularization. Serum levels of high-sensitivity cardiac troponin I (hs-cTnI) and amino-terminal pro B-type natriuretic peptide (NT-proBNP) were quantified as surrogate markers of LV dysfunction. The primary endpoint was defined as all-cause mortality, the secondary endpoint was defined as the composite of all-cause mortality and hospitalization for acute myocardial infarction or heart failure during follow-up. Whereas no associations between EF and the biochemical markers of LV function were found, both GLS and MD correlated positively with increasing levels of hs-cTnI (R = 0.315, P < 0.001 and R = 0.442, P < 0.001, respectively) and NT-proBNP (R = 0.195, P = 0.016 and R = 0.390, P < 0.001, respectively). Median MD was 46 ms (interquartile range [IQR] 37-53) and was successfully quantified in 96% of the patients. During a median follow-up of 8.4 (IQR 8.2-8.8) years, 14 deaths and 29 secondary events occurred. MD was significantly increased in non-survivors, and provided incremental prognostic value when added to EF and GLS. NT-proBNP was superior to the echocardiographic markers in predicting adverse outcomes. MD may be a promising marker of LV dysfunction and adverse prognosis in stable CAD.

Estimating glomerular filtration rate in children: evaluation of creatinine- and cystatin C-based equations.

BACKGROUND: Glomerular filtration rate (GFR) estimated by creatinine- and/or cystatin C-based equations (eGFR) is widely used in daily practice. The purpose of our study was to compare new and old eGFR equations with measured GFR (mGFR) by iohexol clearance in a cohort of children with chronic kidney disease (CKD). METHODS: We examined 96 children (median age 9.2 years (range 0.25-17.5)) with CKD stages 1-5. A 7-point iohexol clearance (GFR7p) was defined as the reference method (median mGFR 66 mL/min/1.73 m2, range 6-153). Ten different eGFR equations, with or without body height, were evaluated: Schwartzbedside, SchwartzCKiD, SchwartzcysC, CAPA, LMREV, (LMREV + CAPA) / 2, FAScrea, FAScysC, FAScombi, FASheight. The accuracy was evaluated with percentage within 10 and 30% of GFR7p (P10 and P30). RESULTS: In the group with mGFR below 60 mL/min/1.73 m2, the SchwartzcysC equation had the lowest median bias (interquartile range; IQR) 3.27 (4.80) mL/min/1.73 m2 and the highest accuracy with P10 of 44% and P30 of 85%. In the group with mGFR above 60 mL/min/1.73 m2, the SchwartzCKiD presented with the lowest bias 3.41 (13.1) mL/min/1.73 m2 and P10 of 62% and P30 of 98%. Overall, the SchwartzcysC had the lowest bias - 1.49 (13.5) mL/min/1.73 m2 and both SchwartzcysC and SchwartzCKiD showed P30 of 90%. P10 was 44 and 48%, respectively. CONCLUSIONS: The SchwartzcysC and the combined SchwartzCKiD present with lower bias and higher accuracy as compared to the other equations. The SchwartzcysC equation is a good height-independent alternative to the SchwartzCKiD equation in children and can be reported directly by the laboratory information system. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov , Identifier NCT01092260, https://clinicaltrials.gov/ct2/show/NCT01092260?term=tondel&rank=2.