[Clinical Outcome of Microsatellite Instability-High Patients Treated with Pembrolizumab and Genetic Counseling].

Prospective studies have demonstrated the efficacy of pembrolizumab in patients with previously treated unresectable or metastatic microsatellite instability-high(MSI-H)cancers. Pembrolizumab has been covered by the Japanese health insurance system since December 2018. The frequency of MSI-H in patients is as low as approximately 2%. In addition, some patients with MSI-H cancers are diagnosed with Lynch syndrome. In the present study, we retrospectively investigated patients who received MSI testing at Kitasato University Hospital from April 2019 to June 2020. We also investigated the therapeutic effect of pembrolizumab for MSI-H cancers and patients who received genetic counseling for Lynch syndrome. Results identified that 5 out of 263 patients who underwent MSI testing(1.9%)had MSI-H. The therapeutic outcomes of pembrolizumab in those patients were as follows: 1(20%)complete response, 3(60%)partial response, and 1(20%) progressive disease. The positive-outcome rate of MSI-H treatment in our institution was comparable to that in the previous reports. The high response rate of pembrolizumab was confirmed in the present study. Four out of 5 patients received genetic counseling at the genetic clinic, and 1 patient underwent genetic testing for Lynch syndrome. No deleterious variant of Lynch syndrome was detected in the genetic testing.

Acrodysostosis and pseudohypoparathyroidism (PHP): adaptation of Japanese patients with a newly proposed classification and expanding the phenotypic spectrum of variants.

Objective: This study aimed to report on 15 Japanese patients with acrodysostosis and pseudohypoparathyroidism (PHP) and analyze them using the newly proposed classification of the EuroPHP network to determine whether this classification system is suitable for Japanese patients. Design: We divided the patients into three groups based on hormone resistance, the number of fingers with short metacarpals, the existence of cone-shaped epiphyses and gene defects. Methods: We carried out clinical, radiological and genetic evaluations of two patients in group A (iPPSD5), six patients in group B (iPPDS4) and seven patients in group C (iPPSD2). Results: Group A consisted of two siblings without hormone resistance who had the most severe bone and physical developmental delays. PDE4D gene defects were detected in both cases. Group B consisted of six patients who showed hormone resistance without hypocalcemia. Short metacarpal bones with corn-shaped epiphyses were observed in all patients. In two cases, PRKAR1A gene defects were detected; however, their clinical and radiological features were not identical. The facial dysmorphism and developmental delay were less severe and PRKAR1A gene defects were detected in case B-3. Severe facial dysmorphism and deformity of metacarpal bones were observed, but no gene defect was detected in case B-1. Group C consisted of seven patients with PHP1a, four of whom had maternally inherited heterozygous inactivating mutations in one of the GNAS genes. The clinical and radiological features of the patients in group C were not identical either. Conclusions: The newly proposed classification is suitable for Japanese patients; however, heterogeneities still existed within groups B and C.

A novel TP63 variant in a patient with ankyloblepharon-ectodermal defect-cleft lip/palate syndrome and Rapp-Hodgkin syndrome-like ectodermal dysplasia.

Ankyloblepharon-ectodermal defect-cleft lip/palate syndrome and Rapp-Hodgkin syndrome are well-known TP63-related autosomal-dominant genetic disorders with various similar ectodermal dysplasias. In this study, whole-exome sequencing revealed a novel, potentially pathogenic TP63 nonsense variant (NM_001114980.2:c.25 C > T: p.Gln9Ter) in a patient with an atypical clinical phenotype. This variant was detected near translation initiation sites and has an effect only on ΔNp63α, the short isoform protein product of the TP63 gene.

A novel TAB2 mutation detected in a putative case of frontometaphyseal dysplasia.

Frontometaphyseal dysplasia (FMD) type 2 is an autosomal dominant disorder characterized by skeletal abnormalities and caused by MAP3K7 mutation. We identified a novel missense mutation in TAB2 associated with FMD in a child with multiple congenital malformations. This case was diagnosed as FMD due to joint contractures and bone deformities. This is the third report of FMD caused by a TAB2 mutation located in the TAK1-binding region.

Improved library preparation protocols for amplicon sequencing-based noninvasive fetal genotyping for RHD-positive D antigen-negative alleles.

OBJECTIVE: We aimed to simplify our fetal RHD genotyping protocol by changing the method to attach Illumina's sequencing adaptors to PCR products from the ligation-based method to a PCR-based method, and to improve its reliability and robustness by introducing unique molecular indexes, which allow us to count the numbers of DNA fragments used as PCR templates and to minimize the effects of PCR and sequencing errors. RESULTS: Both of the newly established protocols reduced time and cost compared with our conventional protocol. Removal of PCR duplicates using UMIs reduced the frequencies of erroneously mapped sequences reads likely generated by PCR and sequencing errors. The modified protocols will help us facilitate implementing fetal RHD genotyping for East Asian populations into clinical practice.

Clinical Genetics in Japan: Efforts of Human Genetics Societies and Related Organizations.

The Japanese government finally started measures to promote the realization of genomic medicine that can promote the accumulation of individual genomic information for improving medical care in 2015. However, readiness in terms of social infrastructure (including legal, administrative, ethical, and educational aspects in Japan) remains inadequate. Associations related to medical genetics have been making consistent efforts to realize genomic medicine by establishing guidelines, nurturing genetic professionals, providing support for constructing cross-disciplinary medical systems, enriching genetic education, etc., and it is important that the Japanese government supports these initiatives.

[In Situ Ductal Carcinoma with Hereditary Breast and Ovarian Cancer Syndrome in a Patient Who Received Contralateral Risk-Reducing Mastectomy-A Case Report].

A woman in her 30s presented to our hospital with the chief complaint of a right breast mass after the birth of her first child. She was diagnosed as having right invasive ductal carcinoma of Luminal-B type and T3N3cM0, stage Ⅲc. While undergoing neoadjuvant chemotherapy, she received genetic counseling and underwent genetic testing and was determined to have deleterious BRCA1 and BRCA2 mutations. After completing chemotherapy, she underwent a right total mastectomy and axillary lymph node dissection. Two years postoperatively, she requested to undergo a contralateral risk-reducing mastectomy( CRRM)of her left breast. Therefore, CT and breast MRI were performed to confirm the absence of contralateral lesions and distant metastases, and subsequently, CRRM was performed. Postoperative pathology results showed non-invasive ductal carcinoma lesions at 5 sites. In the case of hereditary breast and ovarian cancer syndrome such as in this study, lesions may be discovered at an early stage by performing risk-reducing mastectomy.

Detection of novel Fabry disease-associated pathogenic variants in Japanese patients by newborn and high-risk screening.

BACKGROUND: In Japan, newborn and high-risk screening for Fabry disease (FD), an inherited X-linked disorder caused by GLA mutations, using dried blood spots was initiated in 2006. In newborn screening, 599,711 newborns were screened by December 2018, and 57 newborns from 54 families with 26 FD-associated variants were detected. In high-risk screening, 18,235 individuals who had symptoms and/or a family history of FD were screened by March 2019, and 236 individuals from 143 families with 101 FD-associated variants were detected. Totally 3, 116 variants were detected; 41 of these were not registered in Fabry-database.org or ClinVar and 33 were definitely novel. Herein, we report the clinical outcomes and discuss the pathogenicity of the 41 variants. METHODS: We traced nine newborns and 46 individuals with the 33 novel variants, and nine newborns and 10 individuals with eight other variants not registered in the FD database, and analyzed the information on symptoms, treatments, and outcomes. RESULTS: Thirty-eight of the 46 individuals with the 33 novel variants showed symptoms and received enzyme-replacement therapy and/or chaperone treatment. CONCLUSION: Delayed diagnosis should be avoided in patients with FD. Our results will help clinicians diagnose FD and determine the appropriate treatment for patients with these variants.

Correction: Nationwide survey for current clinical status of amniocentesis and maternal serum marker test in Japan.

Since the publication of this paper, the authors noticed that Yosuke Fujii was assigned to the incorrect affiliation. The affiliation information is provided correctly, above.

TRPV6 Variants Interfere with Maternal-Fetal Calcium Transport through the Placenta and Cause Transient Neonatal Hyperparathyroidism.

Transient neonatal hyperparathyroidism (TNHP) is etiologically a heterogeneous condition. One of the etiologies is an insufficient maternal-fetal calcium transport through the placenta. We report six subjects with homozygous and/or compound-heterozygous mutations in the gene encoding the transient receptor potential cation channel, subfamily V, member 6 (TRPV6), an epithelial Ca2+-selective channel associated with this condition. Exome sequencing on two neonates with skeletal findings consistent with neonatal hyperparathyroidism identified homozygous frameshift mutations before the first transmembrane domain in a subject born to first-cousins parents of Pakistani descent as well as compound-heterozygous mutations (a combination of a frameshift mutation and an intronic mutation that alters mRNA splicing) in an individual born to a non-consanguineous couple of African descent. Subsequently, targeted mutation analysis of TRPV6 performed on four other individuals (born to non-consanguineous Japanese parents) with similar X-rays findings identified compound-heterozygous mutations. The skeletal findings improved or resolved in most subjects during the first few months of life. We identified three missense variants (at the outer edges of the second and third transmembrane domains) that alter the localization of the TRPV6: one recurrent variant at the S2-S3 loop and two recurrent variants (in the fourth ankyrin repeat domain) that impair TRPV6 stability. Compound heterozygous loss-of-function mutations for the pathogenic frameshift allele and the allele with an intronic c.607+5G>A mutation resulted in the most severe phenotype. These results suggest that TNHP is an autosomal-recessive disease caused by TRPV6 mutations that affect maternal-fetal calcium transport.

FGFR1 Analyses in Four Patients with Hypogonadotropic Hypogonadism with Split-Hand/Foot Malformation: Implications for the Promoter Region.

Heterozygous loss-of-function mutations of FGFR1 (fibroblast growth factor receptor 1) cause various disorders including hypogonadotropic hypogonadism with split-hand/foot malformation (HH-SHFM). We examined FGFR1 in four Japanese patients with HH-SHFM (cases 1-4) and the mother of case 4 with HH only. Cases 1 and 2 had heterozygous loss-of-function mutations with no dominant negative effect (c.289G>A, p.[G97S]; and c.2231G>C, p.[R744T]), and case 3 had a splice donor site mutation (c.1663+1G>T). Notably, case 4 had a maternally inherited 8,312 bp microdeletion that involved noncoding exon 1U and impaired FGFR1 expression. Furthermore, consistent with the presence of transcription-related histone marks (e.g., H3K4Me3, H3K4Me1, and H3K27Ac) and multiple transcription factor-binding sites around exon 1U, functional studies demonstrated a marked transactivation function of a 414-bp segment harboring the transcription start site. These results support the relevance of FGFR1 mutations to HH-SHFM, and argue for the presence of the FGFR1 core-promoter elements around exon 1U.

Nationwide survey for current clinical status of amniocentesis and maternal serum marker test in Japan.

Prenatal testing has been provided in Japan over the past several decades. However, it is difficult to assess the clinical status of amniocentesis (AC) and maternal serum markers (MSM) because obstetricians can perform these tests without registration. This study aims to investigate the current clinical status of AC and MSM in Japan. We conducted a questionnaire study that was intended for a total of 5622 Japanese obstetrics/gynecology facilities during October 2013 to January 2014. The response rate was 40.8% (2295/5622). Of the 2295 facilities, 864 performed MSM (37.7%), 619 performed AC (27.0%) and 412 performed both (18.0%). The average number of MSM tests was 2.0 per month (range 0-52), and the average number of AC tests was 2.4 per month (range 0-30). Involvement of genetic professionals, such as clinical geneticists (CGs) and certified genetic counselors (CGCs), contribute to a content-rich explanation and management of difficult issues and lengthened the explanation time. Nevertheless, relatively few facilities employed these specialists (MSM: 96/864 and AC: 128/619). This is the first study to highlight the current clinical status of AC and MSM tests in Japan. Active involvement of CGs and CGCs can provide more appropriate genetic counseling for prenatal tests.

Clinical and molecular studies in four patients with SRY-positive 46,XX testicular disorders of sex development: implications for variable sex development and genomic rearrangements.

We report four patients with SRY-positive 46,XX testicular disorders of sex development (46,XX-TDSD) (cases 1-4). Case 1 exhibited underdeveloped external genitalia with hypospadias, case 2 manifested micropenis and cases 3 and 4 showed normal external genitalia. The Xp;Yp translocations occurred between the X- and the Y-differential regions in case 1, between PRKX and inverted PRKY in case 2 and between the X-chromosomal short arm pseudoautosomal region and the Y-differential regions in cases 3 and 4. The distance of the Yp breakpoint from SRY was ~0.75 Mb in case 1, ~6.5 Mb in case 2, ~2.3 Mb in case 3 and ~72 kb in case 4. The Xp;Yp translocation occurred within an 87-bp homologous segment of PRKX and PRKY in case 2, and between non-homologous regions with addition of an 18-bp sequence of unknown origin in case 4. X-inactivation analysis revealed random inactivation in cases 1-4. The results argue against the notion that undermasculinization in 46,XX-TDSD is prone to occur when translocated Yp materials are small (<100 kb of the Y-differential region), and imply that the Xp;Yp translocations result from several mechanisms including non-allelic homologous recombination and non-homologous end joining.

Comprehensive and quantitative multilocus methylation analysis reveals the susceptibility of specific imprinted differentially methylated regions to aberrant methylation in Beckwith-Wiedemann syndrome with epimutations.

PURPOSE: Expression of imprinted genes is regulated by DNA methylation of differentially methylated regions (DMRs). Beckwith-Wiedemann syndrome is an imprinting disorder caused by epimutations of DMRs at 11p15.5. To date, multiple methylation defects have been reported in Beckwith-Wiedemann syndrome patients with epimutations; however, limited numbers of DMRs have been analyzed. The susceptibility of DMRs to aberrant methylation, alteration of gene expression due to aberrant methylation, and causative factors for multiple methylation defects remain undetermined. METHODS: Comprehensive methylation analysis with two quantitative methods, matrix-assisted laser desorption/ionization mass spectrometry and bisulfite pyrosequencing, was conducted across 29 DMRs in 54 Beckwith-Wiedemann syndrome patients with epimutations. Allelic expressions of three genes with aberrant methylation were analyzed. All DMRs with aberrant methylation were sequenced. RESULTS: Thirty-four percent of KvDMR1-loss of methylation patients and 30% of H19DMR-gain of methylation patients showed multiple methylation defects. Maternally methylated DMRs were susceptible to aberrant hypomethylation in KvDMR1-loss of methylation patients. Biallelic expression of the genes was associated with aberrant methylation. Cis-acting pathological variations were not found in any aberrantly methylated DMR. CONCLUSION: Maternally methylated DMRs may be vulnerable to DNA demethylation during the preimplantation stage, when hypomethylation of KvDMR1 occurs, and aberrant methylation of DMRs affects imprinted gene expression. Cis-acting variations of the DMRs are not involved in the multiple methylation defects.

Identification of a novel missense mutation of MAF in a Japanese family with congenital cataract by whole exome sequencing: a clinical report and review of literature.

Congenital cataracts are the most important cause of severe visual impairment in infants. Genetic factors contribute to the disease development and 29 genes are known to cause congenital cataracts. Identifying the genetic cause of congenital cataracts can be difficult because of genetic heterogeneity. V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF) encodes a basic region/leucine zipper transcription factor that plays a key role as a regulator of embryonic lens fiber cell development. MAF mutations have been reported to cause juvenile-onset pulverulent cataract, microcornea, iris coloboma, and other anterior segment dysgenesis. We report on six patients in a family who have congenital cataracts were identified MAF mutation by whole exome sequencing (WES). The heterozygous MAF mutation Q303L detected in the present family occurs in a well conserved glutamine residue at the basic region of the DNA-binding domain. All affected members showed congenital cataracts. Three of the six members showed microcornea and one showed iris coloboma. Congenital cataracts with MAF mutation exhibited phenotypically variable cataracts within the family. Review of the patients with MAF mutations supports the notion that congenital cataracts caused by MAF mutations could be accompanied by microcornea and/or iris coloboma. WES is a useful tool for detecting disease-causing mutations in patients with genetically heterogeneous conditions.

Gain-of-function mutations in RIT1 cause Noonan syndrome, a RAS/MAPK pathway syndrome.

RAS GTPases mediate a wide variety of cellular functions, including cell proliferation, survival, and differentiation. Recent studies have revealed that germline mutations and mosaicism for classical RAS mutations, including those in HRAS, KRAS, and NRAS, cause a wide spectrum of genetic disorders. These include Noonan syndrome and related disorders (RAS/mitogen-activated protein kinase [RAS/MAPK] pathway syndromes, or RASopathies), nevus sebaceous, and Schimmelpenning syndrome. In the present study, we identified a total of nine missense, nonsynonymous mutations in RIT1, encoding a member of the RAS subfamily, in 17 of 180 individuals (9%) with Noonan syndrome or a related condition but with no detectable mutations in known Noonan-related genes. Clinical manifestations in the RIT1-mutation-positive individuals are consistent with those of Noonan syndrome, which is characterized by distinctive facial features, short stature, and congenital heart defects. Seventy percent of mutation-positive individuals presented with hypertrophic cardiomyopathy; this frequency is high relative to the overall 20% incidence in individuals with Noonan syndrome. Luciferase assays in NIH 3T3 cells showed that five RIT1 alterations identified in children with Noonan syndrome enhanced ELK1 transactivation. The introduction of mRNAs of mutant RIT1 into 1-cell-stage zebrafish embryos was found to result in a significant increase of embryos with craniofacial abnormalities, incomplete looping, a hypoplastic chamber in the heart, and an elongated yolk sac. These results demonstrate that gain-of-function mutations in RIT1 cause Noonan syndrome and show a similar biological effect to mutations in other RASopathy-related genes.

Clinical application of array-based comparative genomic hybridization by two-stage screening for 536 patients with mental retardation and multiple congenital anomalies.

Recent advances in the analysis of patients with congenital abnormalities using array-based comparative genome hybridization (aCGH) have uncovered two types of genomic copy-number variants (CNVs); pathogenic CNVs (pCNVs) relevant to congenital disorders and benign CNVs observed also in healthy populations, complicating the screening of disease-associated alterations by aCGH. To apply the aCGH technique to the diagnosis as well as investigation of multiple congenital anomalies and mental retardation (MCA/MR), we constructed a consortium with 23 medical institutes and hospitals in Japan, and recruited 536 patients with clinically uncharacterized MCA/MR, whose karyotypes were normal according to conventional cytogenetics, for two-stage screening using two types of bacterial artificial chromosome-based microarray. The first screening using a targeted array detected pCNV in 54 of 536 cases (10.1%), whereas the second screening of the 349 cases negative in the first screening using a genome-wide high-density array at intervals of approximately 0.7 Mb detected pCNVs in 48 cases (13.8%), including pCNVs relevant to recently established microdeletion or microduplication syndromes, CNVs containing pathogenic genes and recurrent CNVs containing the same region among different patients. The results show the efficient application of aCGH in the clinical setting.