Genetic liability to posttraumatic stress disorder and its association with postpartum depression.

BACKGROUND: Childbirth may be a traumatic experience and vulnerability to posttraumatic stress disorder (PTSD) may increase the risk of postpartum depression (PPD). We investigated whether genetic vulnerability to PTSD as measured by polygenic score (PGS) increases the risk of PPD and whether a predisposition to PTSD in PPD cases exceeds that of major depressive disorder (MDD) outside the postpartum period. METHODS: This case-control study included participants from the iPSYCH2015, a case-cohort of all singletons born in Denmark between 1981 and 2008. Restricting to women born between 1981 and 1997 and excluding women with a first diagnosis other than depression (N = 22 613), 333 were identified with PPD. For each PPD case, 999 representing the background population and 993 with MDD outside the postpartum were matched by calendar year at birth, cohort selection, and age. PTSD PGS was calculated from summary statistics from the Psychiatric Genomics Consortium with LDpred2-auto. Odds ratios (ORs) were estimated using conditional logistic regression adjusted for parental psychiatric history and country of origin, PGS for MDD and age at first birth, and the first 10 principal components. RESULTS: The PTSD PGS was significantly associated with PPD (OR 1.42, 95% CI 1.20-1.68 per standard deviation increase in PTSD PGS) compared to healthy female controls. Genetic PTSD vulnerability in PPD cases did not exceed that of matched female depression cases outside the postpartum period (OR 1.10, 95% CI 0.94-1.30 per standard deviation increase). CONCLUSIONS: Genetic vulnerability to PTSD increased the risk of PPD but did not differ between PPD cases and women with depression at other times.

Genome-wide association study across pediatric central nervous system tumors implicates shared predisposition and points to 1q25.2 (PAPPA2) and 11p12 (LRRC4C) as novel candidate susceptibility loci.

INTRODUCTION: Central nervous system (CNS) tumors constitute the most common form of solid neoplasms in children, but knowledge on genetic predisposition is sparse. In particular, whether susceptibility attributable to common variants is shared across CNS tumor types in children has not been investigated. The purpose of this study was to explore potential common genetic risk variants exhibiting pleiotropic effects across pediatric CNS tumors. We also investigated whether such susceptibility differs between early and late onset of disease. METHOD: A Danish nationwide genome-wide association study (GWAS) of 1,097 consecutive patients (< 15 years of age) with CNS tumors and a cohort of 4,745 population-based controls. RESULTS: For both the overall cohort and patients diagnosed after the age of four, the strongest association was rs12064625 which maps to PAPPA2 at 1q25.2 (p = 3.400 × 10-7 and 9.668 × 10-8, respectively). PAPPA2 regulates local bioavailability of insulin-like growth factor I (IGF-I). IGF-I is fundamental to CNS development and is involved in tumorigenesis across a wide range of different cancers. For the younger children, the strongest association was provided by rs11036373 mapping to LRRC4C at 11p12 (p = 7.620 × 10-7), which encoded protein acts as an axon guidance molecule during CNS development and has not formerly been associated with brain tumors. DISCUSSION: This GWAS indicates shared susceptibility attributable to common variants across pediatric CNS tumor types. Variations in genetic loci with roles in CNS development appear to be involved, possibly via altered IGF-I related pathways.

Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial.

BACKGROUND: Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and interaction with aromatase (encoded by CYP19A1). Use of non-steroidal anti-inflammatory drugs (NSAID) may also affect circulating sex-hormone levels by modifying PPARγ activity. METHODS: In the present study we assessed whether genetic variation in CYP19A1 is associated with risk of BC in a case-control study group nested within the Danish "Diet, Cancer and Health" cohort (ncases = 687 and ncontrols = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions. Association between the CYP19A1 polymorphisms and hormone levels was also examined among 339 non-HRT users. Incidence rate ratios were calculated based on Cox' proportional hazards model. Furthermore, we performed a pilot randomised controlled trial to determine the effect of the PPARG Pro(12)Ala polymorphism and the PPARγ stimulator Ibuprofen on sex-hormone levels following alcohol intake in postmenopausal women (n = 25) using linear regression. RESULTS: Genetic variations in CYP19A1 were associated with hormone levels (estrone: P rs11070844 = 0.009, estrone sulphate: P rs11070844 = 0.01, P rs749292 = 0.004, P rs1062033 = 0.007 and P rs10519297 = 0.03, and sex hormone-binding globulin (SHBG): P rs3751591 = 0.03) and interacted with alcohol intake in relation to hormone levels (estrone sulphate: P interaction/rs2008691 = 0.02 and P interaction/rs1062033= 0.03, and SHBG: P interaction/rs11070844 = 0.03). CYP19A1/rs3751591 was both associated with SHBG levels (P = 0.03) and with risk of BC (Incidence Rate Ratio = 2.12; 95 % Confidence Interval: 1.02-4.43) such that homozygous variant allele carriers had increased levels of serum SHBG and were at increased risk of BC. Acute intake of alcohol decreased blood estrone (P = <0.0001), estrone sulphate (P = <0.0001), and SHBG (P = 0.009) levels, whereas Ibuprofen intake and PPARG Pro(12)Ala genotype had no effect on hormone levels. CONCLUSIONS: Our results suggest that genetically determined variation in CYP19A1 is associated with differences in sex hormone levels. However, the genetically determined differences in sex hormone levels were not convincingly associated with BC risk. The results therefore indicate that the genetically determined variation in CYP19A1 contributes little to BC risk and to alcohol-mediated BC risk. TRIAL REGISTRATION: NCT02463383, June 3, 2015.

Resveratrol reduces the levels of circulating androgen precursors but has no effect on, testosterone, dihydrotestosterone, PSA levels or prostate volume. A 4-month randomised trial in middle-aged men.

BACKGROUND: Resveratrol is a naturally occurring polyphenol with purported inhibitory effects on prostate growth and cancer development. A number of studies have demonstrated that resveratrol reduces prostate growth in animal models and reduces prostate cell growth in vitro. Based on these pre-clinical findings, interest in resveratrol is increasing in relation to the management of benign prostate hyperplasia (BPH) and prostate cancer. So far, no human trials have evaluated the effects of resveratrol on circulating androgens, prostate size, or biochemical markers of prostate size. METHODS: In a randomized placebo controlled clinical study using two doses of resveratrol (150 mg or 1,000 mg resveratrol daily) for 4 months, we evaluated the effects on prostate size, prostate specific antigen (PSA) and sex steroid hormones in 66 middle-aged men suffering from the metabolic syndrome(MetS). RESULTS: At baseline, prostate size and PSA were positively correlated (R = 0.34, P < 0.007) as was prostate size and age (R = 0.37, P < 0.003). Prostate size did not correlate with testosterone, free testosterone, dihydrotestosterone (DHT), or any other androgen precursor at baseline. The highest dose of resveratrol lowered the serum level of androstenedione 24% (P = 0.052), dehydroepiandrosterone (DHEA) 41% (P < 0.01), and dehydroepiandrosterone-sulphate (DHEAS) 50% (p<0.001), compared to the control group. However, prostate size and levels of PSA, testosterone, free testosterone and DHT remained unchanged. CONCLUSION: In this population of middle-aged men suffering from MetS, high dose resveratrol (1,000 mg daily) administration for 4 months significantly lowered serum levels of the androgen precursors androstenedione, DHEA and DHEAS, whereas prostate size and circulating levels of PSA, testosterone, free testosterone, and dihydrotestosterone were unaffected. The present study suggests that resveratrol does not affect prostate volume in healthy middle-aged men as measured by PSA levels and CT acquired prostate volumes. Consequently, we find no support for the use of resveratrol in the treatment of benign prostate hyperplasia.

Short QTc interval in males with klinefelter syndrome-influence of CAG repeat length, body composition, and testosterone replacement therapy.

BACKGROUND: Klinefelter syndrome (KS) is a sex chromosomal aneuploidy (47,XXY) affecting 1/660 males. Based on findings in Turner syndrome, we hypothesized that electrocardiogram (ECG) abnormalities would be present in males with KS. OBJECTIVE: To investigate ECGs in males with KS and compare with controls. METHODS: Case control study of 62 males with KS and 62 healthy males matched on age. The primary outcome parameter was a difference in the ECG presentation between the two groups. The ECGs were analyzed by one blinded examiner (intraobserver variability 0.2-2.1%). The QT-interval was measured using "teach-the-tangent" method excluding the U-wave. QTc was calculated using Bazett's equation, Hodges' equation, and a linear regression model. Body mass index, abdominal fat, and muscle mass as well as sex hormone levels were secondary parameters. The prevalence of mutations in genes related to short QT syndrome was determined in participants with a QTc < 330 ms. RESULTS: Compared to controls, the QTc-interval was shorter (P = 0.02-0.06) in males with KS depending on the applied correction method. QTc was shortest among testosterone (T)-treated males with KS, while untreated and thus hypogonadal KS had QTc interval comparable to controls. No mutations in genes related to short QT syndrome were found. CONCLUSION: We found short QTc interval in males with KS, with further shortening of the QTc interval by T. These results suggest that genes on the X chromosome could be involved in regulation of the QTc interval and that T treatment may aggravate this mechanism.

Mannose-binding lectin gene, MBL2, polymorphisms are not associated with susceptibility to invasive pneumococcal disease in children.

BACKGROUND: Most children are transiently colonized with Streptococcus pneumoniae, but very few develop invasive pneumococcal disease (IPD). Host genetic variation of innate immunity may predispose to IPD. We investigated the effect of genetic variation in the mannose-binding lectin gene, MBL2, on susceptibility and disease severity of IPD in previously healthy children aged <5 years. METHODS: IPD cases were identified through national registries. DNA was obtained from the Danish Neonatal Screening Biobank. Pneumococcal serotypes were determined by Quellung reaction. The associations between MBL2 diplotypes and IPD susceptibility, serotypes, and outcome were investigated using logistic regression analysis. RESULTS: We included 372 cases with meningitis, 907 with bacteremia, and 1263 age- and sex-matched controls; 2372 individuals were successfully genotyped and assigned MBL2 diplotypes. The median age in our combined case series was 13 months. Children with defective diplotypes were not at higher risk for meningitis than children with other diplotypes (odds ratio [OR], 0.85; 95% confidence interval [CI], .56-1.28). Similar results were found for bacteremia (OR, 0.89; 95% CI, .68-1.15) as well as for all cases (OR, 0.87; 95% CI, .70-1.09). There was no association with susceptibility to recurrent IPD (n = 12) for children with defective diplotypes compared with cases with a single episode (OR, 0.53; 95% CI, .07-4.13) and with all controls (OR, 0.46; 95% CI, .06-3.56). There was no association between diplotypes and mortality or between diplotypes and pneumococcal serotypes. CONCLUSIONS: Defective MBL2 polymorphisms did not predict increased IPD susceptibility in children born in Northern Europe.

Joint analysis of SNPs and proteins identifies regulatory IL18 gene variations decreasing the chance of spastic cerebral palsy.

Cerebral palsy (CP) is a permanent disorder, affecting 2-3 per 1,000 live born children, disturbing movement and posture. Spastic limbs affects about 70-80% of the CP children, and this group is the target of our study. CP is considered a multifactorial condition believed to be provoked by, for example, preterm birth, infection during pregnancy, neural disorders, and genetics, to mention some. Interestingly, the cytokine network is believed to be involved in many of these disorders. In this study, including 203 spastic CP cases and 167 controls, we measured the levels of 25 cytokine proteins, and genotyped 159 SNPs in their gene loci. Using logistic regression, we estimated the genetic association of SNP genotypes to spastic CP. In addition, fitting a Tobit regression model for each protein and each SNP in the respective gene loci, we estimated three regression coefficients corresponding three different effects of the genetic variation on the protein level. Intriguingly, two IL18 loci SNPs (rs549908:A>C and rs1290349:C>A) showed a protective effect against spastic CP, and interestingly both were associated to a decreased epidemiological expression of IL-18 protein. By joining protein data to genetic information, we have provided new data suggesting IL18's involvement in the pathogenesis of spastic CP.

DNA methylome profiling using neonatal dried blood spot samples: a proof-of-principle study.

DNA methylation is the most common DNA modification and perhaps the best described epigenetic modification. It is believed to be important for genomic imprinting and gene regulation and has been associated with the development of diseases such as schizophrenia and some types of cancer. Neonatal dried blood spot samples, commonly known as Guthrie cards, are routinely collected worldwide to screen newborns for diseases. Some countries, including Denmark, have been storing the excess neonatal dried blood spot samples in biobanks for decades. Representing a high percentage of the population under a certain age, the neonatal dried blood spot samples are a potential alternative to collecting new samples to study diseases. As such, neonatal dried blood spot samples have previously been used for DNA genotyping studies with excellent results. However, the amount of material available for research is often limited, challenging researchers to generate the most data from a limited quantity of material. In this proof-of-principle study, we address whether two 3.2mm disks punched from a neonatal dried blood spot sample contain enough DNA for genome-wide methylome profiling, measuring 27,578 loci at the same time. We selected two subjects and carried out the following with each: 1) collected an adult whole-blood sample as reference, 2) spotted a fraction of the whole-blood sample onto a similar type of filter paper as used in the newborn screening and stored it for 3years to serve as a dried blood spot reference, and 3) identified the archived neonatal dried blood spot samples, stored for 26-28years, in the Danish Newborn Screening Biobank as a representative of the archived samples. For comparison, we used two different kits for DNA extraction. The DNA, extracted using the Extract-N-Amp Blood PCR kit, was analyzed, and no statistically significant differences were observed (P<0.001) when we compared the methylation profile of the reference whole-blood samples to the dried blood spot references. This indicates that two 3.2mm disks contain enough material for reliable methylome profiling and that storing the whole-blood sample on neonatal dried blood spot filter paper for 3years does not interfere with the outcome of the analysis. Furthermore, we compared the adult DNA methylation profile to the neonatal dried blood spot sample profile. Approximately 50 sites in the subjects were significantly (P<0.001) different in the newborn sample compared with the adult sample. Both being healthy adults and the high quality of the DNA methylation array led to the conclusion that the archived neonatal dried blood spot samples can be used for methylome profiling, despite decades of storage and DNA degradation. In conclusion, we show that reliable methylome data can be obtained from old neonatal dried blood spot samples, by using a reasonable amount of the limited resource. This further adds to the use of neonatal dried blood spot samples in genetic research and screening and paves the way for unique population-based studies of epigenetic modifications after birth.

Archived neonatal dried blood spot samples can be used for accurate whole genome and exome-targeted next-generation sequencing.

Dried blood spot samples (DBSS) have been collected and stored for decades as part of newborn screening programmes worldwide. Representing almost an entire population under a certain age and collected with virtually no bias, the Newborn Screening Biobanks are of immense value in medical studies, for example, to examine the genetics of various disorders. We have previously demonstrated that DNA extracted from a fraction (2×3.2mm discs) of an archived DBSS can be whole genome amplified (wgaDNA) and used for accurate array genotyping. However, until now, it has been uncertain whether wgaDNA from DBSS can be used for accurate whole genome sequencing (WGS) and exome sequencing (WES). This study examined two individuals represented by three different types of samples each: whole-blood (reference samples), 3-year-old DBSS spotted with reference material (refDBSS), and 27- to 29-year-old archived neonatal DBSS (neoDBSS) stored at -20°C in the Danish Newborn Screening Biobank. The reference samples were genotyped using an Illumina Omni2.5M array, and all samples were sequenced on a HighSeq2000 Paired-End flow cell. First, we compared the array single nucleotide polymorphism (SNP) genotype data to the single nucleotide variation (SNV) calls from the WGS and WES SNV calls. We also compared the WGS and WES reference sample SNV calls to the DBSS SNV calls. The overall performance of the archived DBSS was similar to the whole blood reference sample. Plotting the error rates relative to coverage revealed that the error rates of DBSS were similar to that of their reference samples. SNVs called with a coverage<×8 had error rates between 1.5 and 35%, whereas the error rates of SNVs called with a coverage≥8 were <1.5%. In conclusion, the wgaDNA amplified from both new and old neonatal DBSS perform as well as their whole-blood reference samples with regards to error rates, strongly indicating that neonatal DBSS collected shortly after birth and stored for decades comprise an excellent resource for NGS studies of disease.

Combinatorial batching of DNA for ultralow-cost detection of pathogenic variants.

BACKGROUND: Next-generation sequencing (NGS) based population screening holds great promise for disease prevention and earlier diagnosis, but the costs associated with screening millions of humans remain prohibitive. New methods for population genetic testing that lower the costs of NGS without compromising diagnostic power are needed. METHODS: We developed double batched sequencing where DNA samples are batch-sequenced twice - directly pinpointing individuals with rare variants. We sequenced batches of at-birth blood spot DNA using a commercial 113-gene panel in an explorative (n = 100) and a validation (n = 100) cohort of children who went on to develop pediatric cancers. All results were benchmarked against individual whole genome sequencing data. RESULTS: We demonstrated fully replicable detection of cancer-causing germline variants, with positive and negative predictive values of 100% (95% CI, 0.91-1.00 and 95% CI, 0.98-1.00, respectively). Pathogenic and clinically actionable variants were detected in RB1, TP53, BRCA2, APC, and 19 other genes. Analyses of larger batches indicated that our approach is highly scalable, yielding more than 95% cost reduction or less than 3 cents per gene screened for rare disease-causing mutations. We also show that double batched sequencing could cost-effectively prevent childhood cancer deaths through broad genomic testing. CONCLUSIONS: Our ultracheap genetic diagnostic method, which uses existing sequencing hardware and standard newborn blood spots, should readily open up opportunities for population-wide risk stratification using genetic screening across many fields of clinical genetics and genomics.

MCAD deficiency in Denmark.

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common defect of fatty acid oxidation. Many countries have introduced newborn screening for MCADD, because characteristic acylcarnitines can easily be identified in filter paper blood spot samples by tandem mass spectrometry (MS/MS), because MCADD is a frequent disease, and because of the success of early treatment initiated before clinical symptoms have emerged. In Denmark we have screened 519,350 newborns for MCADD by MS/MS and identified 58 affected babies. The diagnosis of MCADD was confirmed in all 58 newborns by mutation analysis. This gives an incidence of MCADD detected by newborn screening in Denmark of 1/8954. In sharp contrast to this we found that the incidence of clinically presenting MCADD in Denmark in the 10 year period preceding introduction of MS/MS-based screening was only 1 in 39,691. This means that four times more newborns with MCADD are detected by screening than what is expected based on the number of children presenting clinically in an unscreened population. The mutation spectrum in the newborns detected by screening is different from that observed in clinically presenting patients with a much lower proportion of newborns being homozygous for the prevalent disease-causing c.985A>G mutation. A significant number of the newborns have genotypes with mutations that have not been observed in patients detected clinically. Some of these mutations, like c.199T>C and c.127G>A, are always associated with a milder biochemical phenotype and may cause a milder form of MCADD with a relatively low risk of disease manifestation, thereby explaining part of the discrepancy between the frequency of clinically manifested MCADD and the frequency of MCADD determined by screening. In addition, our data suggest that some of this discrepancy can be explained by a reduced penetrance of the c.985A>G mutation, with perhaps only 50% of c.985A>G homozygotes presenting with disease manifestations. Interestingly, we also report that the observed number of newborns identified by screening who are homozygous for the c.985A>G mutation is twice that predicted from the estimated carrier frequency. We therefore redetermined the carrier frequency in a new sample of 1946 blood spots using a new assay, but this only confirmed that the c.985A>G carrier frequency in Denmark is approximately 1/105. We conclude that MCADD is much more frequent than expected, has a reduced penetrance and that rapid genotyping using the initial blood spot sample is important for correct diagnosis and counseling.

Biochemical screening of 504,049 newborns in Denmark, the Faroe Islands and Greenland--experience and development of a routine program for expanded newborn screening.

Expanded newborn screening for selected inborn errors of metabolism (IEM) in Denmark, the Faroe Islands and Greenland was introduced in 2002. We now present clinical, biochemical, and statistical results of expanded screening (excluding PKU) of 504,049 newborns during nine years as well as diagnoses and clinical findings in 82,930 unscreened newborns born in the same period. The frequencies of diagnoses made within the panel of disorders screened for are compared with the frequencies of the disorders in the decade preceding expanded newborn screening. The expanded screening was performed as a pilot study during the first seven years, and the experience obtained during these years was used in the development of the routine neonatal screening program introduced in 2009. Methods for screening included tandem mass spectrometry and an assay for determination of biotinidase activity. A total of 310 samples from 504,049 newborns gave positive screening results. Of the 310 results, 114 were true positive, including results from 12 newborns in which the disease in question was subsequently diagnosed in their mothers. Thus, the overall frequency of an IEM in the screening panel was 1:4942 (mothers excluded) or 1:4421 (mothers included). The false positive rate was 0.038% and positive predictive value 37%. Overall specificity was 99.99%. All patients with true positive results were followed in The Center for Inherited Metabolic Disorders in Copenhagen, and the mean follow-up period was 45 months (range 2109 months). There were no deaths among the 102 children, and 94% had no clinically significant sequelae at last follow-up. Our study confirms the higher frequency of selected IEM after implementation of expanded newborn screening and suggests an improved outcome for several disorders. We argue that newborn screening for these disorders should be standard of care, though unresolved issues remain, e.g. about newborns with a potential for remaining asymptomatic throughout life. Well organized logistics of the screening program from screening laboratory to centralized, clinical management is important.

Neonatal Screening for Congenital Adrenal Hyperplasia in Denmark: 10 Years of Experience.

INTRODUCTION: Early detection of salt-wasting congenital adrenal hyperplasia (SW-CAH) is important to reduce CAH-related morbidity. However, neonatal screening has shown to have a low positive predictive value (PPV), especially among preterm newborns. Here, the Danish CAH screening is evaluated by comparing incidence and morbidity of SW-CAH 10 years before and after introduction of screening. Furthermore, sensitivity, specificity, and PPV are determined. METHODS: All newborns in Denmark born during 1999-2018 and diagnosed with SW-CAH were identified in the Danish National Patient Registry and/or at the Department of Clinical Genetics, Rigshospitalet. Newborns with a positive neonatal CAH screening were identified at Statens Serum Institut. Correct diagnosis was evaluated by medical record review. RESULTS: A total of 65 newborns with SW-CAH were identified. The incidence of SW-CAH was 5:100,000 both before and after introduction of screening. Performance of sensitivity and specificity of the screening were 97% and 100%, respectively, and the PPV was 55% for the given period. Stratified according to gestational age, the PPV was 33% and 61% for pre -and fullterm newborns, respectively. Though not significant, the proportion of newborns presenting with SW-crisis decreased after introduction of screening from 29% versus 10% (p = 0.07). DISCUSSION AND CONCLUSION: Neonatal screening for SW-CAH has not led to an increase in the incidence of newborns diagnosed with SW-CAH. The screening algorithm has effectively identified newborns with SW-CAH. After 2009, there was a tendency toward a lower proportion of newborns with SW-crisis at diagnosis. Finally, the study emphasizes the benefits of using second-tier screening as well as repeated screening of premature newborns.

Neonatal antibodies to infectious agents and risk of bipolar disorder: a population-based case-control study.

OBJECTIVE: There is a substantial evidence base linking prenatal exposure to infectious agents and an increased risk of schizophrenia. However, there has been less research examining the potential for these exposures to also contribute to risk for bipolar disorder. The aim of this study was to examine the association between neonatal markers of selected prenatal infections and risk for bipolar disorder. METHODS: Using population-based Danish registers, we examined 127 individuals with a diagnosis of bipolar disorder, and 127 sex and day-of-birth individually matched controls. Based on neonatal dried blood spots, we measured antibodies to herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), cytomegalovirus (CMV), and Toxoplasma gondii. Relative risks were calculated for the matched pairs when examined for optical density units for antibodies to each of the infectious agents. RESULTS: There was no association between any of the neonatal markers of prenatal infection and risk of bipolar disorder. CONCLUSIONS: In contrast with studies of schizophrenia, our analysis does not support maternal infection with HSV-1, HSV-2, CMV, or Toxoplasma gondii as risk factors for bipolar disorder. However, larger study samples are needed, and data on, for example, specific serotypes of Toxoplasma and indicators of the timing of maternal infection are still warranted.

Implementation of SCID Screening in Denmark.

Screening for SCID was added to the Danish Neonatal Screening Program in February 2020. The screening uses a RealtimePCR kit and we here present the results and experiences with the validation of the kit and the first 10 months of screening.

Co-occurring hydrocephalus in autism spectrum disorder: a Danish population-based cohort study.

BACKGROUND: The association between autism spectrum disorder and hydrocephalus is not well understood, despite demonstrated links between autism spectrum disorder and cerebrospinal fluid abnormalities. Based on the hypothesis that autism spectrum disorder and hydrocephalus may, at least in some cases, be two manifestations of a shared congenital brain pathology, we investigated the potential association between autism spectrum disorder and hydrocephalus in a large Danish population-based cohort. METHODS: Patients and controls were obtained from the Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH2012 case-cohort, which includes all patients with selected psychiatric disorders born in Denmark 1981-2005 along with randomly selected population controls (end of follow-up, December 31, 2016). The associations between individual psychiatric disorders and hydrocephalus were estimated using binary logistic regression with adjustment for age and sex. RESULTS: The cohort consisted of 86,571 individuals, of which 14,654 were diagnosed with autism spectrum disorder, 28,606 were population controls, and the remaining were diagnosed with other psychiatric disorders. We identified 201 hydrocephalus cases; 68 among autism spectrum disorder patients and 40 among controls (OR 3.77, 95% CI 2.48-5.78), which corresponds to an absolute risk of 0.46 % (i.e. approximately one in 217 children with autism spectrum disorder had co-occurring hydrocephalus). The autism spectrum disorder-hydrocephalus association was significant over the entire subgroup spectrum of autism spectrum disorder. CONCLUSIONS: Given the considerable risk of hydrocephalus among patients with autism spectrum disorder, we suggest that patients with autism spectrum disorder should be evaluated for co-occurring hydrocephalus on a routine basis as timely neurosurgical intervention is important. Likewise, attention must be paid to traits of autism spectrum disorder in children with hydrocephalus. The results of this study call for future investigations on a potential shared aetiology between hydrocephalus and autism spectrum disorder, including the role abnormal CSF dynamics in the pathogenesis of autism spectrum disorder.

Identification of genetic loci associated with nocturnal enuresis: a genome-wide association study.

BACKGROUND: Nocturnal enuresis (bedwetting) is a common disorder affecting 10-16% of 7-year-old children globally. Nocturnal enuresis is highly heritable, but its genetic determinants remain unknown. We aimed to identify genetic variants associated with nocturnal enuresis and explore its genetic architecture and underlying biology. METHODS: We did a genome-wide association study (GWAS) of nocturnal enuresis. Nocturnal enuresis cases were identified in iPSYCH2012, a large Danish population-based case cohort established to investigate mental disorders, on the basis of 10th revision of the International Statistical Classification of Diseases (ICD-10) diagnoses and redeemed desmopressin prescriptions in Danish registers. The GWAS was done in a genetically homogeneous sample of unrelated individuals using logistic regression with relevant covariates. All genome-wide significant variants were analysed for their association with nocturnal enuresis in an independent Icelandic sample from deCODE genetics. Standardised polygenic risk scores for attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder were constructed from summary statistics of large GWASs and analysed for association with nocturnal enuresis. FINDINGS: The GWAS included 3882 nocturnal enuresis cases and 31 073 controls. We found two loci at chromosome 6 and chromosome 13 significantly associated with nocturnal enuresis. Six genetic variants at the two loci (five variants at chromosome 6q16.2 and one variant at chromosome 13q22.3) surpassed the threshold for genome-wide significance (p<5 × 10-8). There were two lead variants: rs9376454 (chromosome 6q16.2), with an odds ratio (OR) of 1·199 (95% CI 1·135-1·267; p=9·91 × 10-11), and rs60721117 (chromosome 13q22.3), with an OR of 1·149 (1·095-1·205; p=1·21 × 10-8). All associated variants in the chromosome 6 locus were replicated (p<8 × 10-3) in the independent Icelandic cohort of 5475 nocturnal enuresis cases and 303 996 controls, whereas the associated variant in the chromosome 13 locus showed nominal significant association (p=0·031). The percentage of nocturnal enuresis phenotypic variance explained by the common genetic variants was 23·9-30·4%. Polygenic risk for ADHD was associated with nocturnal enuresis (OR 1·06, 95% CI, 1·01-1·10; p=0·011). Among the potential nocturnal enuresis risk genes mapped, PRDM13 and EDNRB have biological functions associated with known pathophysiological mechanisms in nocturnal enuresis, and SIM1 regulates the formation of the hypothalamic neuroendocrine lineage that produces arginine vasopressin, a well known nocturnal enuresis drug target. INTERPRETATION: This study shows that common genetic variants contribute considerably to nocturnal enuresis, and it identifies potential nocturnal enuresis risk genes with roles in sleep, urine production, and bladder function. Given that available treatments target these mechanisms, any of the identified genes and their functional gene networks are potential drug targets. FUNDING: The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Stanley Foundation.

Association Between Childhood Green Space, Genetic Liability, and the Incidence of Schizophrenia.

Childhood exposure to green space has previously been associated with lower risk of developing schizophrenia later in life. It is unclear whether this association is mediated by genetic liability or whether the 2 risk factors work additively. Here, we investigate possible gene-environment associations with the hazard ratio (HR) of schizophrenia by combining (1) an estimate of childhood exposure to residential-level green space based on the normalized difference vegetation index (NDVI) from Landsat satellite images, with (2) genetic liability estimates based on polygenic risk scores for 19 746 genotyped individuals from the Danish iPSYCH sample. We used information from the Danish registers of health, residential address, and socioeconomic status to adjust HR estimates for established confounders, ie, parents' socioeconomic status, and family history of mental illness. The adjusted HRs show that growing up surrounded by the highest compared to the lowest decile of NDVI was associated with a 0.52-fold (95% confidence interval [CI]: 0.40 to 0.66) lower schizophrenia risk, and children with the highest polygenic risk score had a 1.24-fold (95% CI: 1.18 to 1.30) higher schizophrenia risk. We found that NDVI explained 1.45% (95% CI: 1.07 to 1.90) of the variance on the liability scale, while polygenic risk score for schizophrenia explained 1.01% (95% CI: 0.77 to 1.46). Together they explained 2.40% (95% CI: 1.99 to 3.07) with no indication of a gene-environment interaction (P = .29). Our results suggest that risk of schizophrenia is associated additively with green space exposure and genetic liability, and provide no support for an environment-gene interaction between NDVI and schizophrenia.

Genetic predisposition to hypertension is associated with preeclampsia in European and Central Asian women.

Preeclampsia is a serious complication of pregnancy, affecting both maternal and fetal health. In genome-wide association meta-analysis of European and Central Asian mothers, we identify sequence variants that associate with preeclampsia in the maternal genome at ZNF831/20q13 and FTO/16q12. These are previously established variants for blood pressure (BP) and the FTO variant has also been associated with body mass index (BMI). Further analysis of BP variants establishes that variants at MECOM/3q26, FGF5/4q21 and SH2B3/12q24 also associate with preeclampsia through the maternal genome. We further show that a polygenic risk score for hypertension associates with preeclampsia. However, comparison with gestational hypertension indicates that additional factors modify the risk of preeclampsia.

Genotyping whole-genome-amplified DNA from 3- to 25-year-old neonatal dried blood spot samples with reference to fresh genomic DNA.

Stored surplus of dried blood spot (DBS) samples from neonatal screening programs constitute a vast potential for large genetic epidemiological studies. However, age of the samples and the small amounts of DNA available may limit their usage. In this study we validate genotyping accuracy and efficiency of whole-genome-amplified DNA (wgaDNA) obtained from stored DBS samples, with reference to fresh genomic DNA from the same individuals. DBS samples from 29 volunteers, stored for up to 25 years, in the Danish Neonatal Screening Biobank were included and three DNA extraction methods, each using one 3.2 mm disk, were evaluated. Four whole-genome amplification kits, and one re-amplification kit, were used. Thirty-one SNPs were genotyped using the Sequenom platform and the wgaDNA samples calls were compared with their references for accuracy and efficiency evaluation. The genotype calls done blinded by the user had in many setups a 100% call- and concordance rate. Our results showed that genotyping performance is dependent on the combination of extraction procedure and amplification method, whereas years of storage did not seem to influence in this study. Based on these results we conclude that DBS samples should be considered a reliable and potential resource for future genotyping studies.