👤 Momoko Horikoshi

Pilocytic astrocytoma (PA) is the most common pediatric tumor, typically located in the cerebellum, with spontaneous regression observed mainly in patients with neurofibromatosis type 1 (NF1). However, spontaneous regression of PA without NF1 is rarely reported. Here, we describe a case of spontaneous regression of PA without NF1, located in the left frontal lobe with FGFR1-TACC1 fusion, in a 14-year-old boy who presented with epilepsy. Initial MRI revealed a lesion in the left middle frontal gyrus, and subsequent follow-up MRI demonstrated spontaneous regression. Despite this regression, the patient's seizures persisted, leading to epileptic focus resection. Pathological examination confirmed PA with characteristic histological findings and FGFR1-TACC1 fusion. This case suggests that FGFR1-TACC1 fusion may be linked to spontaneous regression of PA, even in the absence of NF1. Surgical intervention may remain necessary in cases of epilepsy associated with PA, regardless of tumor regression. Show less

Although hundreds of genome-wide association studies-implicated loci have been reported for adult obesity-related traits, less is known about the genetics specific for early-onset obesity and with only a few studies conducted in non-European populations to date. Searching for additional genetic variants associated with childhood obesity, we performed a trans-ancestral meta-analysis of 30 studies consisting of up to 13 005 cases (≥95th percentile of body mass index (BMI) achieved 2-18 years old) and 15 599 controls (consistently <50th percentile of BMI) of European, African, North/South American and East Asian ancestry. Suggestive loci were taken forward for replication in a sample of 1888 cases and 4689 controls from seven cohorts of European and North/South American ancestry. In addition to observing 18 previously implicated BMI or obesity loci, for both early and late onset, we uncovered one completely novel locus in this trans-ancestral analysis (nearest gene, METTL15). The variant was nominally associated with only the European subgroup analysis but had a consistent direction of effect in other ethnicities. We then utilized trans-ancestral Bayesian analysis to narrow down the location of the probable causal variant at each genome-wide significant signal. Of all the fine-mapped loci, we were able to narrow down the causative variant at four known loci to fewer than 10 single nucleotide polymorphisms (SNPs) (FAIM2, GNPDA2, MC4R and SEC16B loci). In conclusion, an ethnically diverse setting has enabled us to both identify an additional pediatric obesity locus and further fine-map existing loci. Show less

Donor cell leukemia (DCL) occurs after allogeneic hematopoietic stem cell transplantation. Several mechanisms, including occult leukemic/preleukemic subclones in the donor graft and germline predisposition to leukemia, are proposed to be associated with DCL's molecular pathogenesis. We report a comprehensive genetic analysis of a patient with KMT2A-rearranged DCL after allogeneic bone marrow transplantation for refractory cytopenia of childhood. We performed a whole-exome sequencing of the recipient's peripheral blood before transplant and the donor's peripheral blood and the recipient's bone marrow at the time of DCL diagnosis. RNA sequencing was also performed to detect fusion genes in DCL blasts. There were no germline mutations that were associated with a predisposition to leukemia in the recipient and donor. Furthermore, there were no detectable somatic alterations except KMT2A-MLLT10 and other related gene fusions in DCL. KMT2A-MLLT10 was not detectable in the donor's bone marrow. We propose a novel pattern of the molecular pathogenesis of DCL solely involving a genetic mutation acquired after transplant with no identifiable genetic factor related to the donor and recipient. Show less

A large number of genetic loci are associated with adult body mass index. However, the genetics of childhood body mass index are largely unknown. We performed a meta-analysis of genome-wide association studies of childhood body mass index, using sex- and age-adjusted standard deviation scores. We included 35 668 children from 20 studies in the discovery phase and 11 873 children from 13 studies in the replication phase. In total, 15 loci reached genome-wide significance (P-value < 5 × 10(-8)) in the joint discovery and replication analysis, of which 12 are previously identified loci in or close to ADCY3, GNPDA2, TMEM18, SEC16B, FAIM2, FTO, TFAP2B, TNNI3K, MC4R, GPR61, LMX1B and OLFM4 associated with adult body mass index or childhood obesity. We identified three novel loci: rs13253111 near ELP3, rs8092503 near RAB27B and rs13387838 near ADAM23. Per additional risk allele, body mass index increased 0.04 Standard Deviation Score (SDS) [Standard Error (SE) 0.007], 0.05 SDS (SE 0.008) and 0.14 SDS (SE 0.025), for rs13253111, rs8092503 and rs13387838, respectively. A genetic risk score combining all 15 SNPs showed that each additional average risk allele was associated with a 0.073 SDS (SE 0.011, P-value = 3.12 × 10(-10)) increase in childhood body mass index in a population of 1955 children. This risk score explained 2% of the variance in childhood body mass index. This study highlights the shared genetic background between childhood and adult body mass index and adds three novel loci. These loci likely represent age-related differences in strength of the associations with body mass index. Show less

The aim of the present study was to explore the role of variations with modest effects (previously identified by a large-scale meta-analysis in European populations) in the genetic background of type 2 diabetes (T2D) and diabetes-related traits in a Japanese population. We enrolled 2632 Japanese subjects with T2D and 2050 non-diabetic subjects. We analyzed nine single-nucleotide polymorphisms (SNPs), including rs340874 (PROX1), rs4607517 (GCK), rs2191349 (DGKB-TMEM195), rs7034200 (GLIS3), rs10885122 (ADRA2A), rs174550 (FADS1), rs11605924 (CRY2), rs10830963 (MTNR1B) and rs35767 (IGF1). rs340874 (PROX1) and rs174550 (FADS1) were significantly associated with T2D (P=0.0078, OR: 1.12; and P=0.0071, OR: 1.12, respectively). Subjects with more risk alleles related to nine SNPs had an increased risk of T2D (P=0.0017), as well as a higher fasting plasma glucose level (P=0.018), higher HbA(1c) level (P=0.013) and lower HOMA-β (P=0.033) compared with subjects who had fewer risk alleles. We identified a significant association of a SNP of FADS1 and a SNP near PROX1 with T2D in a Japanese population. The present findings suggest that inclusion of SNPs with a tendency to increase the disease risk captured more of the genetic background of T2D than that revealed by only assessing significant SNPs. Show less

Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis. Show less