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Atypical psychological symptoms frequently occur in early-onset Alzheimer’s disease (EOAD), which makes it difficult to differentiate it from other psychiatric disorders. We report the case of a 28-year-old woman with EOAD, carrying a presenilin-1 mutation (S170P), who was initially misdiagnosed with schizophrenia because of prominent psychiatric symptoms in the first 1–2 years of the disease. Amyloid-β positron emission tomography (PET) showed remarkably high tracer uptake in the striatum and thalamus. Tau PET showed widespread cortical uptake and relatively low uptake in the subcortical and medial temporal regions. Our case advocates for considering EOAD diagnosis for young patients with psychiatric and atypical cognitive symptoms.

Familial hypophosphatemic rickets (FHR) is a disorder characterized by phosphate wasting and hypophosphatemia due to defects in renal phosphate transport regulation. There are 4 known inherited forms of FHR that differ in their molecular causes. Very few studies have been conducted that focused on the molecular analysis of FHR in Koreans. Eighteen mutations of the PHEX gene have been identified to this date in Korea. Herein, we report the clinical case of a 24-month-old boy presenting with bowed legs and short stature. The biochemical profile showed hypophosphatemia with decreased tubular reabsorption of phosphate. Several family members were identified with short stature and genu varum. Therefore, he was diagnosed with FHR. To identify the molecular causes of FHR, we performed targeted gene panel sequencing and found a novel hemizygous missense variant, c.1949T>C (p.Leu650Pro), in the PHEX gene. This variant was also detected in the boy’s mother who exhibited genu varum and short stature.

Congenital lipoid adrenal hyperplasia (CLAH) is one of the most fatal conditions caused by an abnormality of adrenal and gonadal steroidogenesis. CLAH results from loss-of-function mutations of the steroidogenic acute regulatory (STAR) gene; the disease manifests with electrolyte imbalances and hyperpigmentation in neonates or young infants due to adrenocortical hormone deficiencies, and 46, XY genetic male CLAH patients can be phenotypically female. Meanwhile, some patients with STAR mutations develop hyperpigmentation and mild signs of adrenal insufficiency, such as hypoglycemia, after infancy. These patients are classified as having nonclassic CLAH (NCCLAH) caused by STAR mutations that retain partial activity of STAR. We present the case of a Korean boy with normal genitalia who was diagnosed with NCCLAH. He presented with whole-body hyperpigmentation and electrolyte abnormalities, which were noted at the age of 17 months after an episode of sepsis with peritonitis. The compound heterozygous mutations p.Gly221Ser and c.653C>T in STAR were identified by targeted gene-panel sequencing. Skin hyperpigmentation should be considered an important clue for diagnosing NCCLAH.

Background Combined methylmalonic acidemia and homocystinuria is a rare inherited disorder of intracellular cobalamin metabolism caused by biallelic variants in one of the following genes: MMACHC (cblC), MMADHC (cblD), LMBRD1 (cblF), ABCD4 (cblJ), THAP11 (cblX‐like), and ZNF143 (cblX‐like), or a hemizygous variant in HCFC1 (cblX). Prenatal diagnosis of combined methylmalonic acidemia with homocystinuria is crucial for high‐risk couples since the disorder can be life‐threatening for offspring. We would like to describe two infant deaths both of which are likely attributable to cblC despite not having a genetic confirmation, and subsequent pregnancy and prenatal genetic testing. Methods Parental clinical exome sequencing and targeted Sanger sequencing of MMACHC gene in amniotic fluid was performed to check the carrier status of the fetus. Results Parental clinical exome sequencing revealed a heterozygous pathogenic variant [NM_015506.2:c.217C>T (p.Arg73*)] in the MMACHC gene of the mother and [NM_015506.2:c.609G>A (p.Trp203*)] in the MMACHC gene of the father. Targeted Sanger sequencing of MMACHC gene in amniotic fluid revealed that the fetus carried only one nonsense variant [NM_015506.2:c.609G>A (p.Trp203*)], which was inherited from the father. The mother delivered a healthy baby and the neonate did not show any symptoms or signs of combined methylmalonic acidemia and homocystinuria after birth. Conclusion We present a case of prenatal diagnosis with parental exome sequencing, which successfully diagnosed the carrier status of the fetus and parents in a combined methylmalonic acidemia and homocystinuria family., Figure shows the Sanger sequencing analysis of the family with methylmalonic acidemia and homocystinuria cobalamin C type. We did successfuly prenatal diagnosis of combined methylmalonic acidemia and homocystinuria cobalamin C type using clinical exome sequencing and targeted gene analysis.

Vitamin A and carotenoids are fat-soluble micronutrients that play important role as powerful antioxidants modulating oxidative stress and cancer development. Breast cancer is the most common malignancy in women. As the risk of breast cancer is dependent on various lifestyle factors such as dietary modifications, there is increasing interest surrounding the anti-cancerous properties of vitamin A and carotenoids. Despite the suggested protective roles of vitamin A and carotenoids in breast cancer development, their clinical application for the prevention and treatment of breast cancer is limited. In this narrative review, we discuss the roles of vitamin A and carotenoids along with the evaluation method of vitamin A status. We also exhibit the association of genetic variations involved in metabolism of vitamin A and carotenoids with cancers and other diseases. We demonstrate the epidemiological evidence for the relationship of vitamin A and carotenoids with breast cancer risk, their effects on cancer mechanism, and the recent updates in clinical practice of vitamin A or carotenoids as a potential therapeutic agent against breast cancer. This review provides insight into the preventive and therapeutic roles of vitamin A and carotenoids in breast cancer development and progression.

Tatton-Brown-Rahman Syndrome (TBRS), an overgrowth syndrome caused by heterozygous mutation of DNMT3A, first was described in 2014. Approximately 60 DNMT3A variants, including 32 missense variants, have been reported, with most missense mutations located on the DNMT3A functional domains. Autosomal dominant inheritance by germ-line mutation of DNMT3A has been reported, but vertical transmission within a family is extremely rare. Herein, we report the first Korean family with maternally inherited TBRS due to the novel heterozygous DNMT3A variant c.118G>C p.(Glu40Gln), located outside the main functional domain and identified by multigene panel sequencing. The patient and her mother had typical clinical features, including tall stature during childhood, macrocephaly, intellectual disability, and characteristic facial appearance. TBRS shows milder dysmorphic features than other overgrowth syndromes, potentially leading to underdiagnosis and underestimated prevalence; thus, targeted multigene panel sequencing including DNMT3A will be a useful tool in cases of overgrowth and unexplained mild intellectual disability for early diagnosis and genetic counseling.

Congenital hypothyroidism (CH) is the most common endocrine disorder in neonates and infants with an incidence of one in 2,000 to one in 4,000 newborns. Primary CH can be caused by thyroid dysgenesis and thyroid dyshormonogenesis. CH due to a TG gene mutation is one cause of thyroid dyshormonogenesis and can be characterized by goitrous CH with absent or low levels of serum thyroglobulin (Tg). In the present case, a 15-day-old neonate was referred to us with elevated thyroid stimulating hormone detected during a neonatal screening test. At the age of 34 months, extensive genetic testing was performed, including targeted exome sequencing for hypothyroidism, and revealed compound heterozygous mutations in the TG gene. Sanger sequencing of both parents’ DNA samples revealed a c.3790T> C (p.Cys1264Arg) mutation located at exon 17 inherited from the mother, and a c.4057C> T (p.Gln1353*) mutation located at exon 19 was inherited from the father. The c.4057C> T (p.Gln1353*) mutation located at exon 19 has never been reported and, therefore, is a new discovery. We report a case of primary permanent CH with compound heterozygous mutations of the TG gene, including a novel mutation.

Purpose: To analyze the characteristics of somatic mutations and copy number alterations (CNAs) in Korean patients with advanced prostate cancer (PCa) by use of the Oncomine Comprehensive Panel (ThermoFisher Scientific) and low-coverage, whole-genome sequencing (LC-WGS). Materials and Methods: We retrospectively analyzed PCa tissues obtained from 14 patients with advanced PCa (metastatic tumor, 12 [85.7%]; nonmetastatic castration-resistant PCa, 1 [7.1%]; pT3b, 1 [7.1%]) from 2009 to 2017. The Oncomine Comprehensive Panel included a total of 143 genes. Moreover, LC-WGS was performed to detect CNAs of the entire genome. Two plasma samples matched with tumor tissues were analyzed using LC-WGS to compare the chromosomal aberration patterns between circulating tumor DNA and tumor tissue. Results: Genetic alterations were most frequently observed in the androgen receptor (AR) (42.9%, n=6/14), TP53 (14.3%, n=2/14), and PTEN (14.3%, n=2/14) genes in the Oncomine panel. AR amplification was the most common CNA (35.7%, n=5/14). As a result of LC-WGS, CNAs were confirmed in about 92.9% (n=13/14) of the samples in regions Xq12, 8q24.21, and 11q13.3 (gains) and in regions 6q16.1, 8p23.1, 10q25.1, 16q24.2, 18q12.3, Xq25, and Xq26.3 (losses). All CNAs identified in the Oncomine panel matched the results of LC-WGS. Additionally, LC-WGS of two plasma samples that matched tumor tissues revealed that CNA patterns of plasma samples (circulating tumor DNA) were very similar to those detected in tumor samples. Conclusions: Our data showed that the characteristics of mutations and CNAs in Korean patients with advanced PCa were similar to those observed in previous studies.

Maternal copy number variation (CNV), especially at the X chromosome is an important cause of false positive noninvasive prenatal test (NIPT) results for sex chromosomal aneuploidy. In addition, some maternal CNV can cause significant anomalies if the male fetus was inherited the X chromosome with CNV. During 1000 high risk Korean NIPT, we incidentally detected two cases of maternal X chromosomal CNV which can cause abnormal phenotype in a male fetus. The first false-positive NIPT case (47, XXY) was due to a maternal 0.5 Mb duplication at Xq28, including the MECP2 gene. The second is a case of an 8-Mb deletion on maternal Xq24q25, including GRIA3 and XIAP genes.

Vitamin D hydroxylation-deficient rickets type 1A (VDDR1A, OMIM 264700) is a rare autosomal recessive inherited disorder. Pathogenic variants in the CYP27B1 gene lead to loss of 1α-hydroxylase activity. We report the case of a 22-month-old toddler who presented with growth retardation and delayed development. The patient exhibited the typical laboratory findings of VDDR1A, including hypocalcemia (calcium: 5.2 mg/dL), elevated serum level of alkaline phosphatase (2,600 U/L), elevated serum level of intact-parathyroid hormone (238 pg/mL), low 1,25(OH)2D3 level (11.2 pg/mL), and normal 25(OH)D3 level (40.7 ng/mL). His height and weight were 76.5 cm and 9.5 kg, respectively (both

Background Although sorafenib is the global standard first-line systemic treatment for unresectable hepatocellular carcinoma (HCC), it does not have reliable predictive or prognostic biomarkers. Circulating cell-free DNA (cfDNA) has shown promise as a biomarker for various cancers. We investigated the use of cfDNA to predict clinical outcomes in HCC patients treated with sorafenib. Methods This prospective biomarker study analyzed plasma cfDNA from 151 HCC patients who received first-line sorafenib and 14 healthy controls. The concentration and VEGFA-to-EIF2C1 ratios (the VEGFA ratio) of cfDNA were measured. Low depth whole-genome sequencing of cfDNA was used to identify genome-wide copy number alteration (CNA), and the I-score was developed to express genomic instability. The I-score was defined as the sum of absolute Z-scores of sequenced reads on each chromosome. The primary aim of this study was to develop cfDNA biomarkers predicting treatment outcomes of sorafenib, and the primary study outcome was the association between biomarkers with treatment efficacy including disease control rate (DCR), time to progression (TTP) and overall survival (OS) in these patients. Results The cfDNA concentrations were significantly higher in HCC patients than in healthy controls (0.71 vs. 0.34 ng/μL; P

Vanishing white matter (VWM) disease is an autosomal recessive disorder that affects the central nervous system of a patient, and is caused by the development of pathogenic mutations in any of the EIF2B1-5 genes. Any dysfunction of the EIF2B1-5 gene encoded eIF2B causes stress-provoked episodic rapid neurological deterioration in the patient, followed by a chronic progressive disease course. We present the case of a patient with an infantile-onset VWM with the pre-described specific clinical course, subsequent neurological aggravation induced by each viral infection, and the noted consequent progression into a comatose state. Although the initial brain magnetic resonance imaging did not reveal specific pathognomonic signs of VWM to distinguish it from other types of demyelinating leukodystrophy, the next-generation sequencing studies identified heterozygous missense variants in EIF2B3, including a novel variant in exon 7 (C706G), as well as a 0.008% frequency reported variant in exon 2 (T89C). Hence, the characteristic of unbiased genomic sequencing can clinically affect patient care and decisionmaking, especially in terms of the consideration of genetic disorders such as leukoencephalopathy in pediatric patients.

Liquid biopsies have increasingly shown clinical utility. Although next-generation sequencing has been widely used for the detection of somatic mutations from plasma, performance characteristics vary by platform. Therefore, thorough validation is mandatory for clinical use. This study aimed to evaluate the analytical validity of the Oncomine Pan-Cancer Cell-Free Assay. A massively parallel sequencing for the assay was performed using the Ion S5 XL System with Ion 540 kit. The analytical sensitivity and precision were evaluated using pre-characterized reference materials. The specificity was evaluated using plasma from healthy subjects. A comparison with the Cobas EGFR Mutation Test v2 was performed using reference materials and plasma from lung cancer patients. For SNVs and short indels, the analytical sensitivities at variant allele frequencies (VAFs) of 0.1%, 0.5%, and 1% were 50%, 93.4%, and 100% with 20 ng of input, respectively. The overall precision of the true positive variants was 98% at a VAF of 1% with 20 ng input. The assay showed a similar sensitivity to that of the Cobas EGFR Mutation Test v2 at a VAF of 0.5% with 20 ng of input and 100% concordance on clinical samples. The Pan-Cancer Cell-Free Assay can be applied to detect EGFR mutations in advanced lung cancer patients, although follow-up studies will be needed to evaluate the analytical validity for other types of genes and aberrations using clinical samples.

Skeletal dysplasia (SD), a heterogeneous disease group with rare incidence and various clinical manifestations, is associated with multiple causative genes. For clinicians, accurate diagnosis of SD is clinically and genetically difficult. The development of next-generation sequencing (NGS) has substantially aided in the genetic diagnosis of SD. In this study, we conducted a targeted NGS of 437 genes – included in the nosology of SD published in 2019 – in 31 patients with a suspected SD. The clinical and genetic diagnoses were confirmed in 16 out of the 31 patients, and the diagnostic yield was 51.9%. In these patients, 18 pathogenic variants were found in 13 genes (COL2A1, MYH3, COMP, MATN3, CTSK, EBP, CLCN7, COL1A2, EXT1, TGFBR1, SMAD3, FIG4, and ARID1B), of which, four were novel variants. The diagnosis rate was very high in patients with a suspected familial SD and with radiological evidence indicating clinical SD (11 out of 15, 73.3%). In patients with skeletal involvement and other clinical manifestations including dysmorphism or multiple congenital anomalies, and various degrees of developmental delay/intellectual disability, the diagnosis rate was low (5 out of 16, 31.2%) but rare syndromic SD could be diagnosed. In conclusion, NGS-based gene panel sequencing can be helpful in diagnosing SD which has clinical and genetic heterogeneity. To increase the diagnostic yield of suspected SD patients, it is important to categorize patients based on the clinical features, family history, and radiographic evidence.

The incidence of vancomycin-associated acute kidney injury (VAKI) varies from 5–43%, and early detection of VAKI is important in deciding whether to discontinue nephrotoxic agents. Oxidative stress is the main mechanism of VAKI, and serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) have been examined with respect to their involvement in ischemia/reperfusion damage in experimental animal models. In the current study, we assessed 5-HT and 5-HIAA as novel biomarkers for detecting VAKI in patients who have infections or compromised renal function, using a mass spectrometry–based metabolomics approach. We conducted amino acid profiling analysis and measurements of 5-HT and 5-HIAA using serum from subjects with VAKI (n = 28) and non-VAKI control subjects (n = 69), consisting of the infection subgroup (n = 23), CKD subgroup (n = 23), and healthy controls (HCs, n = 23). 5-HT was significantly lower in the VAKI group than in the non-VAKI groups, and the concentration of 5-HIAA and the ratio of 5-HIAA to 5-HT (5-HIAA/5-HT) showed higher values in the VAKI group. The infection subgroup presented a significantly greater 5-HIAA/5-HT ratio compared with the HC subgroup. Our study revealed that increased 5-HIAA/5-HT ratio has the potential to act as a VAKI surrogate marker, reflecting acute oxidative stress and inflammation.

Common side effects of mycophenolate mofetil (MMF) are diarrhea, leukopenia, and infectious complication. The polymorphisms of enzymes affecting MMF clearance could be related to MMF toxicity, and in vitro study revealed that high MMF levels might cause endothelial dysfunction. A 7-year-old Korean male with end-stage renal disease on peritoneal dialysis due to mesangial proliferative glomerulonephritis received a kidney transplantation (KT) from a deceased donor, and immunosuppressive medications including MMF, tacrolimus, and methylprednisolone were started after KT. The patient developed oliguria immediately after surgery, and therapeutic plasmapheresis was initiated with continuous renal replacement therapy for the possibility of graft dysfunction and nephrotic syndrome relapse. Renal function recovered 4 days later, but the patient developed ascites. Diagnostic paracentesis revealed findings that were interpreted as uncomplicated ascites in cirrhosis, not of renal origin. Abdominal ultrasonography showed increased parenchymal echogenicity without cirrhotic change in the liver. Based on a case report and differential diagnosis, we replaced MMF with azathioprine, and 4 weeks later a sudden increment in urine output was detected. Eleven months after KT, the patient is free from ascites. The UGT2B7 802 polymorphism was tested, and wild-type UGT2B7 802 was detected, which is related to low MMF clearance. The low clearance of MMF by UGT2B7 802 wild-type polymorphism might have led to MMF toxicity affecting endothelial dysfunction. This case suggests that refractory ascites could be induced by MMF, and endothelial damage is a possible mechanism.

Herein, we present a rare case of co-occurring Duchenne muscular dystrophy (DMD) and frontometaphyseal dysplasia 1 (FMD1), two different X-linked diseases, in a 7-year-old boy. He presented with proximal muscle weakness and elevated creatine phosphokinase levels. A multiplex ligation-dependent probe amplification study ofDMDrevealed thede novoduplications of exons 2–37, thereby confirming the diagnosis of DMD. Initial evaluation revealed atypical features, such as facial dysmorphism, multiple joint contractures, and severe scoliosis, at an early age. However, these were overlooked and were assumed to be atypical manifestations of DMD. Then, the patient's maternal cousin was diagnosed with FMD1 with pathogenic missense variant inFLNA(NM_001110556.2: c.3557C>T/p.Ser1186Leu). A family genetic test revealed that the patient and his mother had the same pathogenic variant inFLNA. The patient's atypical manifestations were considered symptoms of FMD1. Therefore, if one disease does not fully explain the patient's clinical features, an expanded genetic study is needed to detect coincidental disease.

Background: Craniofrontonasal syndrome is a rare, X-linked disorder in which heterozygous females ironically reported the majority of patients and is caused by in the EFNB1 gene located at chromosome Xq13.1. Unlike previous reports, we present a female infant with a de novo EFNB1 missense mutation that was demonstrated in clinical diagnosis as global developmental delay (GDD) and brain anomaly without frontonasal dysplasia or other malformation. Case Presentation: This study reports the genetic analysis of a 4-month-old female infant presenting brain anomaly and GDD. She was the only child of unrelated parents. Early developmental was characterized by delays in fine motor, achieving gross motor, language, and social–cognitive milestones. She could not control her head or hold objects until 4 months of age. Brain magnetic resonance imaging revealed schizencephaly and dysgenesis of corpus callosum. Trio-based whole-exome sequencing revealed a heterozygous c.943C>T (p.Pro315Ser) in the EFNB1. Sanger sequencing confirmed this heterozygous alteration occurring in a dominant de novo manner, as a consequence of phenotypic and genotypic wild type in both parents. Conclusion: EFNB1 mutation is considered for a child with schizencephaly, and further study focusing on phenotyping is required to understand the possible contribution of environmental impact and genetic modifier in the expression of EFNB1.

Limb-girdle muscular dystrophy type R2 dysferin-related (LGMD R2 dysferin-related), a phenotype of dysferlinopathy, usually begins with pelvic girdle weakness. A 35-year-old male presented with right leg pain for 2 weeks without a previous history of limb weakness. Magnetic resonance imaging of the lumbar spine showed disc extrusion at L5–S1 and incidental severe fatty degeneration of the lumbar erector spinae. Physical examination demonstrated no definite limb weakness. Serum creatine kinase levels were elevated. Genetic testing using a targeted gene-sequencing panel identified compound heterozygous variants NM_003494.3(DYSF) c.[1284+2T>C]; [5303G>A]. Computed tomography revealed fatty degeneration of lower-limb muscles, which was mild in the adductor muscles and severe in the gluteus minimus. Immunohistochemistry staining of the vastus lateralis showed under-expression of dysferlin. This patient was diagnosed with LGMD R2 dysferin-related. Thus, unusual fatty degeneration of the lumbar paraspinalis can be a manifestation of dysferlinopathy.

X-linked hypophosphatemic rickets is caused by loss-of-function mutations in PHEX, which encodes a phosphate-regulating endopeptidase homolog. We report a 26-year-old man with X-linked hypophosphatemic rickets who showed decreased serum phosphate accompanied by bilateral genu valgum and short stature. He had received medical treatment with vitamin D (alfacalcidol) and phosphate from the age of 3 to 20 years. He underwent surgery due to valgus deformity at the age of 14 and 15. Targeted gene panel sequencing for Mendelian genes identified a nonsense mutation in PHEX (c.589Cgt;T; p.Gln197Ter) and a mosaic pattern where only 38% of sequence reads showed the variant allele. This mutation was not found in his mother, who had a normal phenotype. This is a case of a sporadic nonsense mutation in PHEX and up to date, this is the first case of a mosaic mutation in PHEX in Korea.

Floating-Harbor syndrome is a rare autosomal dominant genetic disorder associated with SRCAP mutation. To date, approximately 50 cases of Floating-Harbor syndrome have been reported, but none have been reported in Korea yet. Floating-Harbor syndrome is characterized by delayed bony maturation, unique facial features, and language impairment. Here, we present a 6-year-old boy with a triangular face, deep-set protruding eyes, low-set ears, wide nose with narrow nasal bridge, short philtrum, long thin lips, clinodactyly, and developmental delay that was transferred to our pediatric clinic for genetic evaluation. He showed progressive delay in the area of language and cognition-adaption as he grew. He had previously undergone chromosomal analysis at another hospital due to his language delay, but his karyotype was normal. We performed targeted exome sequencing, considering several syndromes with similar phenotypes. Library preparation was performed with the TruSight One sequencing panel, which enriches the sample for about 4,800 genes of clinical relevance. Massively parallel sequencing was conducted with NextSeq. An identified variant was confirmed by Sanger sequencing of the patient and his parents. Finally, the patient was confirmed as the first Korean case of Floating-Harbor syndrome with a novel SRCAP (Snf2 related CREBBP activator protein) mutation (c.7732dupT, p.Ser2578Phefs*6), resulting in early termination of the protein; it was not found in either of his healthy parents or a control population. To our knowledge, this is the first study to describe a boy with Floating-Harbor syndrome with a novel SRCAP mutation diagnosed by targeted exome sequencing in Korea.

Aim To investigate the clinicopathologic and genetic correlations between double primary endometrial and colorectal cancer related to Lynch syndrome and to analyze germline mutations in mismatch repair genes in endometrial cancer patients in Korea. Methods Thirteen patients diagnosed with pathologically endometrial and colorectal cancer between January 2005 and November 2016 in a single institution were enrolled in the study. The medical records were retrospectively analyzed. The genetic mutational information of endometrial cancer in Korea was retrieved from the literature review. Results Endometrial cancer was diagnosed first in eight (62%) patients, and one patient was diagnosed with colorectal cancer first. Endometrioid adenocarcinoma was reported in 10 of 13 (77%) endometrial cancer patients. Endometrial cancer was found at the low uterine segment in three patients. Three of four patients had high microsatellite instability. The loss of mismatch repair proteins was confirmed in 7 of 11 cases using immunohistochemistry. Four patients fulfilled clinical criteria based on a family history of cancer. Overall, the incidence of suspected Lynch syndrome was 77% (10/13). Four of them underwent genetic testing and three were found to have a pathogenic germline mutation. A possible founder mutation, c.1757_1758insC in MLH1, was observed in 21 germline mutation information from literature review. Conclusion The present study describes the clinicopathologic data of double primary endometrial and colorectal cancer patients and supports that these patients should undergo closed approach for Lynch syndrome. Moreover, a possible founder mutation in Korean endometrial cancer patients was identified.

Objective The aim of the present study was to investigate unclassified variants (UVs) in BRCA1 and 2 of Korean patients with ovarian cancer. Methods We retrospectively analyzed 138 patients diagnosed with ovarian/fallopian tubal/peritoneal cancer between January 2013 and January 2016, whose BRCA genetic test results and clinical characteristics were available for review. Patient peripheral blood lymphocyte specimens were assessed for BRCA mutations and variations by direct sequencing. Identified UVs were classified according to several algorithms. Results The results of genetic testing revealed 31 (22.5%, 31/138) pathogenic BRCA mutations (24 BRCA1, 7 BRCA2 mutations). The BRCA1 c.390C>A mutation was observed in 4 patients (12.9%, 4/31). Thirty-four (24.6%, 34/138) BRCA UVs were identified in 33 patients. Of these, the BRCA1 c.4883T>C and BRCA2 c.8187G>T variants were each detected in 4 patients (4/34, 11.8%). According to the used algorithms and cosegregation test, the BRCA1 c.5339T>C and BRCA2 c.8437_8439delGGA variants were both predicted to be likely pathogenic. Conclusions The 2 identified likely pathogenic UVs require further verification with clinical evidence. Clarifying the clinical significance of UVs is an increasingly important step for cancer treatment in the current era of precision medicine.

Over 100 types of congenital disorders of glycosylation (CDG) have been reported and the number is rapidly increasing. However, each type is very rare and is problematic to diagnose. Mannosyl-oligosaccharide glucosidase (MOGS)-CDG (CDG type IIb) is an extremely rare CDG that has only been reported in three patients from two unrelated families. Using targeted exome sequencing, we identified another patient affected by this condition. This patient had increased serum trisialotransferrin levels. Importantly, a review of the features of all four patients revealed the recognizable clinical hallmarks of MOGS-CDG. The distinct dysmorphic features of this condition include long eyelashes, retrognathia, hirsutism, clenched overlapped fingers, hypoventilation, hepatomegaly, generalized edema, and immunodeficiency.

X-linked intellectual disability (XLID) is a genetically heterogeneous disorder involving more than 100 genes known to date. Here, we describe a Korean male infant with global developmental delay. He had neither facial dysmorphism nor skeletal abnormalities. Bayley scale of infant and toddler development third edition (Bayley-III) measured at age of 2 years revealed marked global developmental delays without Marfanoid habitus, structural brain abnormalities, or epilepsy. The patient's cognitive, motor, and language developmental ages were 8-9 months, 12 months, and 9 months, respectively. Targeted next-generation sequencing revealed a de novo mutation [NM_001008222.2(ZDHHC9): c.286C > T (p.(Arg96Trp))] in the affected patient. This mutation has been reported previously in a family XLID with Marfanoid features. Sanger sequencing analysis of the proband and his parents revealed that the missense mutation was present in the proband only (absent in his parents). This indicates that the mutation is de novo in origin. To the best of our knowledge, this is the first report describing sporadic XLID with de novo ZDHHC9 mutation identified by targeted next-generation sequencing.

Noonan syndrome (NS) is a genetic disorder caused by autosomal dominant inheritance and is characterized by a distinctive facial appearance, short stature, chest deformity, and congenital heart disease. In individuals with NS, germline mutations have been identified in several genes involved in the RAS/mitogen-activated protein kinase signal transduction pathway. Because of its clinical and genetic heterogeneity, the conventional diagnostic protocol with Sanger sequencing requires a multistep approach. Therefore, molecular genetic diagnosis using targeted exome sequencing (TES) is considered a less expensive and faster method, particularly for patients who do not fulfill the clinical diagnostic criteria of NS. In this case, the patient showed short stature, dysmorphic facial features suggestive of NS, feeding intolerance, cryptorchidism, and intellectual disability in early childhood. At the age of 16, the patient still showed extreme short stature with delayed puberty and characteristic facial features suggestive of NS. Although the patient had no cardiac problems or chest wall deformities, which are commonly present in NS and are major concerns for patients and clinicians, the patient showed several other characteristic clinical features of NS. Considering the possibility of a genetic disorder, including NS, a molecular genetic study with TES was performed. With TES analysis, we detected a pathogenic variant of c.458A > T in KRAS in this patient with atypical NS phenotype and provided appropriate clinical management and genetic counseling. The application of TES enables accurate molecular diagnosis of patients with nonspecific or atypical features in genetic diseases with several responsible genes, such as NS.

Background As syndromic short stature and overgrowth are heterogeneous and the list of causative genes is rapidly expanding, there is an unmet need for identifying genetic causes based on conventional gene testing or karyotyping. Early diagnosis leads to the proper management of the patient and providing genetic counseling for family members at risk in a timely manner. Materials and methods We conducted targeted exome sequencing to identify the genetic causes of undiagnosed syndromic short stature or overgrowth in 15 pediatric patients from 13 families in Korea. We applied targeted exome sequencing using the Next Seq platform and a TruSight One panel. Results Among the 13 families, 6 different disorders in 8 patients with short stature or overgrowth were identified, and the diagnostic yield was 46.2%. One boy with overgrowth had a TGFB3 gene mutation. In the short stature group, Coffin-Lowry syndrome (CLS), trichorhinophalangeal syndrome, DYRK1A haploinsufficiency syndrome, short stature with optic atrophy and Pelger-Huet anomaly syndrome with recurrent hepatitis, and type 4 Meier-Gorlin syndrome were identified. One CLS patient had a co-existing monogenic disease, congenital glaucoma, caused by the compound heterozygote mutations of the CYP1B1 gene. Conclusion Targeted exome sequencing is a powerful method for diagnosing syndromic growth disorders. It enables us to understand molecular pathophysiology and investigate new treatments for growth disorders.

Background: Autosomal recessive primary microcephaly (Microcephaly Primary Hereditary, MCPH) is a rare disorder, affecting 1 in 10,000 children in areas where consanguineous marriages are common. WDR62 gene mutations are the second most common cause of MCPH. Herein, we report a case of primary microcephaly caused by two novel WDR62 mutations, which is, to our knowledge, the first such case report in East Asia.Case presentation: A 6-year-old girl visited our outpatient clinic as a result of microcephaly and delayed development. The patient was born at 36 weeks 4 days through cesarean section. Her birth weight was 1.8 kg (G). The patient's parents were identified as heterozygous carriers for each variation.Conclusion: We report on two novel heterozygous mutations in East Asia. Our data expand the understanding of WDR62 mutations.

Hereditary sensory and autonomic neuropathy (HSAN) 2B is a rare disease and has been reported mostly in offspring of consanguineous parents. Here we report the case of a patient born to non-consanguineous parents who was diagnosed with HSAN 2B caused due to a novel frameshift mutation (NM_001034850.2: c.765dupT/p.Gly256TrpfsTer7) in the RETREG1 gene and paternal uniparental isodisomy of chromosome 5. Uniparental isodisomy of chromosome 5 is also a rare condition, and these two rare events lead to homozygous expression of a recessive mutation, as in the present case. Clinicians should be aware that autosomal recessive disorders due to homozygous variants can occur because of uniparental disomy in offspring of non-consanguineous parents.

Background Multigene panel sequencing (MGPS) is the first‐line option in diagnostic testing for genetically heterogeneous but clinically similar conditions, such as neuromuscular disorders (NMDs). In this study, we aimed to assess the utility of comprehensive NMD MGPS and the need for updated panels. Methods All patients were analyzed by either of two versions of the NMD MGPS and by chromosomal microarray and karyotype testing. Four patients with negative NMD MGPS results underwent whole exome sequencing. Results In total, 91 patients were enrolled, and a genetic diagnosis was made in 36 (39.6%); of these, 33 were diagnosed by the comprehensive NMD MGPS, two were confirmed by chromosomal microarray, and one was diagnosed by whole exome sequencing. For MGPS, the diagnostic yield of Version 2 (19/52; 36.5%) was a little higher than that of Version 1 (14/39; 35.9%), and one gene identified in Version 2 was not included in Version 1. A total of 36 definitive and nine possible causative variants were identified, of which 17 were novel. Conclusion A more comprehensive panel for NMD MGPS can improve the diagnostic efficiency in genetic testing. The rapid discovery of new disease‐causing genes over recent years necessitates updates to existing gene panels.

Background Early‐onset myopathies show a wide spectrum of phenotypes and are composed of various types of inherited neuromuscular diseases, making it difficult to diagnose. TTN mutation‐related myopathy is a known cause of early‐onset myopathy. Since a next‐generation sequencing (NGS) has enabled sequencing of the vast amount of DNA, TTN, which is the longest coding sequence of any human gene, mutations can now be revealed. We report a 10‐year‐old female with severe congenital muscular weakness and delayed motor development since birth. Methods Next‐generation sequencing as well as electromyography and muscle biopsy were performed. Results To date, she is incapable of walking alone. Her younger sister had similar but more severe symptoms with respiratory failure. In electromyography, short‐duration, small‐amplitude motor unit action potential, and early recruitment patterns were observed in the involved proximal muscles, suggesting myopathy. Muscle histopathology showed a specific atrophy of increased fiber size variability, frequent nuclear internalization, as well as degeneration and regeneration of fibers with type I fiber predominance, consistent with the findings of a previous report about congenital titinopathy. A NGS study revealed two different possible pathogenic variants in TTN: (a) canonical splicing mutation in the intron 105 (c. 29963‐1G>C) and (b) frameshift and truncating mutation in the exon 339 (c.92812dup/p.Arg30938LysfsTer15). All variants were confirmed by conventional Sanger sequencing. Conclusion We propose that unbiased genomic sequencing can be helpful in screening patients with early‐onset myopathy.

Introduction: Congenital hypothyroidism can be caused by aplasia or hypoplasia of the thyroid gland, ectopic thyroid, or dyshormonogenesis. Thyroid function test, thyroid ultrasonography, and thyroid scintigraphy may be helpful in diagnosis. Molecular genetic approach can be used to identify the genetic causes. In this study, diagnostic exome sequencing (DES) including 23 genes associated with congenital hypothyroidism was performed to identify the genetic causes of congenital hypothyroidism. Methods: The patients who were diagnosed as permanent congenital hypothyroidism and agreed to the genetic test were included in the study. We reviewed the clinical information, laboratory tests, and imaging findings based on medical records, retrospectively. Genetic test was performed with an informed consent. Results: A total of 26 children were included in the study. Twelve (46%) were boys and 14 (54%) were girls (M:F 1:1.16). Morphologically, there were 1 (3%) hypoplasia and 1 (3%) agenesis. Twelve (46%) showed ectopic thyroid, and 12 (46%) had normally positioned thyroid. Eighteen (69%) patients were diagnosed within one month of age, and 8 (31%) were diagnosed after one month later. Initial thyroid function test revealed 112.68±55 ng/dL of T3, 0.71±0 ng/dL of fT4, and 77.26±112uIU/mL of TSH. Eighteen (69%) showed overt hypothyroidism and 8 (31%) patients were in subclinical hypothyroidism. On recent follow-up, the mean age was 10.85 years. All of them are taking levothyroxine and the mean levothyroxine dose is 2.15ug/kg/day. In four (15%) patients, pathogenic mutations were found. There were heterozygous mutations of the gene TSHR in 2 patients, compound heterozygous mutation of TG gene in 1 patient, and compound heterozygous mutation of DUOX2 gene in 1 patient. In addition, fifteen (57%) patients showed several VUS (variants of uncertain significance) in at least one of TRH, TRHR, TSHR, SLC26A4, PAX8, TG, TPO, DUOX2, DUOXA2, and POU1F1 genes by DES. Conclusion: We could find pathogenic mutations in 4 patients (15%) among 26 patients with permanent congenital hypothyroidism by DES.

Introduction: Pyruvate dehydrogenase complex deficiency (PDHD) is a rare genetic mitochondrial disorder that is characterized by the broad clinical manifestations from lactic acidosis in neonate to chronic neurodegenerative conditions. Incidence and prevalence of PDHD are unknown because of early lethality and difficulty of diagnosis. Case Presentation: We report a case of preterm male infant born at 31 + 3/7 weeks gestation with a birth weight of 1,310 g by cesarean section. He presented with scoliosis, polydactyly and severe metabolic acidosis at birth. Corpus callosum agenesis and increased parenchymal echogenicity were detected by cranial ultrasound. Pyruvate and lactate in blood and CSF were elevated, and lactate-pyruvate ratio was normal. Next-generation sequencing (NGS) technique identified a novel PDHA1 mutation, c.1157-1162del (p.Phe386Lys387del) on X chromosome in him and his mother. Conclusions: PDHD is a rare and fatal disease in case of neonatal onset. This case demonstrates early diagnosis of PDHD in preterm infant using NGS technique.

Background: Differential diagnosis of developmental delay (DD) and/or intellectual disability (ID) is challenging because of the diversity of phenotypic manifestations as DD/ID patients usually have combined congenital malformations, autism-spectrum disorders, and/or seizure disorder. Thus, unbiased genomic approaches are needed to discover genetic alterations leading to DD and/or ID. Objective: The aim of this study was to investigate the clinical usefulness of targeted next-generation sequencing (NGS) to investigate genetic causes in 35 Korean patients with unexplained DD/ID. Methods: Targeted next-generation sequencing (NGS) using the TruSight One Panel was analyzed in 35 patients with unexplained DD/ID. Sanger sequencing was used to confirm candidate variants, and to define genetic inheritance mode of candidate variant as familial segregation testing. Results: Of 35 patients with DD and/or ID, 10 were found to have underlying genetic etiology and carried X-linked recessive inheritance of ZDHHC9 or autosomal dominant inheritance of SMARCB1, CHD8, LAMA5, NSD1, PAX6, CACNA1H, MBD5, FOXP1, or KCNK18 mutations. No autosomal recessive inherited mutation was identified in this study. As a result, the diagnostic yield of DD/ID by targeted NGS was 29% (10/35), mostly involving may be de novo mutation present in the proband only. A total of seven may be de novo mutations, one paternally inherited, and one maternally inherited mutations that had been reported previously to concede the genetic pathogenesis as known DD and/or ID genes were found in nine patients with available inheritance pattern except LAMA5. Mutations in nine causative genes were detected in patients with similar DD/ID phenotypes in the OMIM database, providing support for genetic evidence as the cause of DD and/or ID. Conclusion: Targeted NGS through singleton analysis with phenotype-first approaches was able to explain 10 out of 35 DD/ID cases. However, the excavation of plausible genetic causes may be de novo, and X-linked disease-causative variants in DD/ID-associated genes requires further genetic analysis.

Rational: Kallmann syndrome (KS) is a genetic gonadotropin-releasing hormone deficiency associated with hyposmia or anosmia and characterized by various modes of inheritance. Patient concerns: A 16-year-old male did not reach puberty and was associated with hypogonadotropic hypogonadism and anosmia. His magnetic resonance imaging of brain revealed the absence of the olfactory bulb. Diagnosis: His karyotype was 46 XY. Sanger sequencing of the KAL1 gene revealed no mutations. Diagnostic exome sequencing identified a prokineticin-receptor 2 (PROKR2) gene variant, c.337T > C (p.Tyr113His), previously reported to be a pathogenic mutation; we confirmed the presence of the mutation via Sanger sequencing of the coding exons of PROKR2. His apparently unaffected mother and sister, but not his father, were heterozygous for the PROKR2 Tyr113His mutation. Lessons: This work advances our understanding of the role played by PROKR signaling and the mode of inheritance of the gene in patients with KS.

Methyl-CpG-binding domain 5 (MBD5)-associated neurodevelopmental disorder caused by 2q23.1 or MBD5-specific mutation has been recently identified as a genetic disorder associated with autism spectrum disorders. Phenotypic features of 2q23.1 deletion or disruption of MBD5 gene include severe intellectual disability, seizure, significant speech impairment, sleep disturbance, and autistic-like behavioural problems. Here we report a 7-year-old girl with intellectual disability and epilepsy without previous clinical diagnosis. Diagnostic exome sequencing identified a novel frameshift mutation c.254_255delGA (p.Arg85Asnfs*6) in the MBD5 gene of the proband and her father. The proband's father with normal intelligence showed subclinical manifestations observed in subsequent investigations. Clinical manifestations, disease course, and molecular findings of the involvement of MBD5 gene in this family suggest an unusual MBD5-related neurodevelopmental disorder. Moreover, this report demonstrates the critical role of next-generation sequencing technique in characterizing such a rare disorder with variable or no clinical manifestation and providing opportunity to develop effective preventive measures such as pre-implantation genetic diagnosis.

Purpose While there is an urgent need for diagnosis and therapeutic intervention in patients with primary immunodeficiency diseases (PIDs), current genetic tests have drawbacks. We retrospectively reviewed the usefulness of flow cytometry (FCM) as a quick tool for immunophenotyping and functional assays in patients suspected to have PIDs at a single tertiary care institute. Methods Between January 2001 and June 2018, patients suspected of having PIDs were subjected to FCM tests, including lymphocyte subset analysis, detection of surface- or intracellular-target proteins, and functional analysis of immune cells, at Samsung Medical Center, Seoul, Korea. The genetic diagnosis was performed using Sanger or diagnostic exome sequencing. Results Of 60 patients diagnosed with definite or probable PID according to the European Society of Immune Deficiencies criteria, 24 patients were provided with useful information about immunological dysfunction after initial FCM testing. In 10 patients, the PID diagnosis was based on abnormal findings in FCM testing without genetic tests. The FCM findings provided strong evidence for the diagnosis of severe combined immunodeficiency (n = 6), X-linked chronic granulomatous diseases (CGD) (n = 6), leukocyte adhesion deficiency type 1 (n = 3), X-linked agammaglobulinemia (n = 11), autoimmune lymphoproliferative syndrome-FASLG (n = 1), and familial hemophagocytic lymphohistiocytosis type 2 (n = 1), and probable evidence for autosomal recessive-CGD (n = 2), autosomal dominant-hyper-immunoglobulin E (IgE)-syndrome (n = 1), and STAT1 gain-of-function mutation (n = 1). In PIDs derived from PIK3CD (n = 2), LRBA (n = 2), and CTLA4 mutations (n = 3), the FCM test provided useful evidence of immune abnormalities and a tool for treatment monitoring. Conclusions The initial application of FCM, particularly with known protein targets on immune cells, would facilitate the timely diagnosis of PIDs and thus would support clinical decisions and improve the clinical outcome.

Introduction Various phenotypes have been identified for MYH7 gene mutation-related myopathy. Here, we describe a patient with severe muscular weakness and skeletal deformity with de novo heterozygous MYH7 gene mutation. Patient concerns A 33-year-old woman presented with early onset of muscular weakness, with delayed motor development during infancy. At age 8 years, she was unable to walk, with signs of skeletal deformity, including the progression of kyphoscoliosis. At age 31 years, she developed dyspnea. Diagnosis She diagnosed with esophageal hiatal hernia with abdominal CT. In electromyography, short duration, small amplitude motor unit action potential (MUAP), and early recruitment patterns were observed in the involved proximal muscles, suggesting myopathy. Muscle histopathology showed fiber-type disproportion. Interventions Next-generation sequencing study revealed a heterozygous in-frame deletion variation in the exon 14 of the MYH7 gene (c.1498_1500del/p.Glu500del), which is a novel variation confirmed by conventional Sanger sequencing. Compared with the parental test, this variant was concluded as de novo. Outcomes She received laparoscopic hiatal hernia repair and Nissen fundoplication for esophageal hiatal hernia. After surgery, her postural dyspnea improved. As there is no fundamental treatment for MYH7-related myopathies, she continued conservative treatment for her symptoms. Conclusion Here, we presented a rare case of de novo mutation of the myosin head domain in the MYH7 gene. This report broadens both the phenotypic and genotypic spectra of MYH7-related myopathies.

e15582 Background: Although neoadjuvant chemoradiation (nCRT) plus surgery or definitive CRT (dCRT) are the standard treatment for locally advanced ESCC, there are no reliable clinical tools for predicting prognosis or monitoring treatment response for CRT in ESCC. We aimed to identify a biomarker for predicting outcomes using cfDNA in ESCC patients (pts) receiving CRT. Methods: This prospective biomarker study analyzed pretreatment plasma cfDNA from pts with nCRT plus surgery (n = 23) and pts with dCRT for locally advanced ESCC (n = 17) at Asan Medical Center in South Korea from Jul. 2017 to Jun. 2018. Low depth whole-genome sequencing of cfDNA was used to identify CNA and I-score was developed to express genomic instability. I-score was defined as the sum of absolute Z-scores of sequenced reads on each chromosome. Results: The pathologic complete response (pCR) was achieved in 7 pts (30.4%) in the nCRT group, and the clinical complete response (cCR) was achieved in 3 pts (17.6%) and clinical partial response (cPR) in 8 pts (47.1%) in the dCRT. The baseline cfDNA concentrations were no significant association with the clinical T stage (cT 1-2 vs. cT 3-4; 0.27 vs. 0.28 ng/μL; p = 0.752), pathologic response (pCR vs. non-pCR; 0.26 vs. 0.30 ng/μL; p = 0.270), ypT stage (ypT 0-2 vs. ypT 3-4; 0.28 vs. 0.36 ng/μL; p = 0.161) and ypTNM stage (ypTNM 1 vs. ypTNM 2-4; 0.26 vs. 0.36 ng/μL; p = 0.065). When analyzing cfDNA concentration before and after CRT, cfDNA concentration was significantly increased after CRT (0.31 vs. 0.55 ng/μL; p = 0.007). The baseline I-score was not associated with baseline clinical stage, but was significantly associated with ypT stage (ypT 1-2 vs. 3-4; 30.4 vs 839.1; p = 0.009), time to progression (median TTP; 11.8 mo in the I-score-low group vs. 6.1 mo in the I-score-high group; p = 0.036), and overall survival (median OS; not reached vs. 10.4 mo; p = 0.046) in the nCRT group. In the dCRT group, I-score was significantly associated with higher disease progression rate (33.3 vs. 58.8%; p = 0.024) with tendency of distant metastasis (33.5 vs. 57.1%; p = 0.490), and short response duration (median, 5.7 mo in the I-score-high group vs not reached in the I-score-low group). Conclusions: The cfDNA concentration is not a good biomarker for prognostication and monitoring the course of treatment in ESCC pts treated with CRT. But the I-score, an indicator of genomic instability in ctDNA, was a significant predictor of poor prognosis.

To identify pathogenic variants in 107 Korean patients with sporadic frontotemporal dementia (FTD), 46 genes related to FTD, amyotrophic lateral sclerosis, and other dementias were screened by next-generation sequencing. Hexanucleotide repeats in C9orf72 gene were also tested by repeat-primed polymerase chain reaction. Next-generation sequencing revealed one known pathogenic variant (c.708+1G>A) in the GRN gene in a patient with behavioral variant FTD (bvFTD). In addition, a novel in-frame deletion (c.2675_2683del) in the CSF1R gene was identified in a patient with bvFTD who had severe bifrontal atrophy with frontal subcortical white matter changes. Novel compound heterozygous variants in the AARS2 gene, c.1040+1G>A and c.636G>A (p.Met212Ile), were found in a patient with bvFTD. Forty-six variants of uncertain significance were detected in other patients. None of the patients had expanded hexanucleotide repeats in C9orf72. These results show that pathogenic variants of known FTD genes are rare in Korean FTD patients but the CSF1R and AARS2 genes should be screened for a genetic diagnosis of FTD or other dementias.

A 10-year-old male and his family members visited a pediatric hematology clinic due to coagulopathy. Laboratory tests indicated von Willebrand disease (vWD) in all the family members. We conducted diagnostic exome sequencing for confirmation. The patient was confirmed to be a compound heterozygote for vWD: c.2574C > G (p.Cys858Trp) from his father (known variant of vWD type 1) and c.3390C > T (p.Pro1127_Gly1180delinsArg) from his mother (variant known to result in exon 26 skipping in vWD type 2A). He was managed with factor VIII and von Willebrand factor complex concentrate during palatoplasty due to bleeding despite pre-operative desmopressin injection. The operation was completed successfully.