Proline-rich transmembrane protein 2 (PRRT2) is the leading cause of paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile epilepsy (BFIE), and infantile convulsions with choreoathetosis (ICCA). Reduced penetrance of PRRT2 has been observed in previous studies, whereas the exact penetrance has not been evaluated well. The objective of this study was to estimate the penetrance of PRRT2 and determine its influencing factors. We screened 222 PKD index patients and their available relatives, identified 39 families with pathogenic or likely pathogenic (P/LP) PRRT2 variants via Sanger sequencing, and obtained 184 PKD/BFIE/ICCA families with P/LP PRRT2 variants from the literature. Penetrance was estimated as the proportion of affected variant carriers. PRRT2 penetrance estimate was 77.6% (95% confidence interval (CI) 74.5%-80.7%) in relatives and 74.5% (95% CI 70.2%-78.8%) in obligate carriers. In addition, we first observed that penetrance was higher in truncated than in non-truncated variants (75.8% versus 50.0%, P = 0.01), higher in Asian than in Caucasian carriers (81.5% versus 68.5%, P = 0.004), and exhibited no difference in gender or parental transmission. Our results are meaningful for genetic counseling, implying that approximately three-quarters of PRRT2 variant carriers will develop PRRT2-related disorders, with patients from Asia or carrying truncated variants at a higher risk.
Dystonia ; Epilepsy, Benign Neonatal/genetics* ; Humans ; Membrane Proteins/genetics* ; Mutation ; Nerve Tissue Proteins/genetics* ; Pedigree ; Penetrance ; Seizures/genetics*

PURPOSE: We investigated the clinical relevance and spectrum of BRCA1/2 mutations in Korean ovarian cancer (KoOC) patients. MATERIALS AND METHODS: Two hundred seventy-nine KoOC patients were enrolled from three university hospitals between 2012 and 2017. Their peripheral blood samples were obtained for BRCA1/2 mutation analysis by direct sequencing. Clinicopathological characteristics were retrospectively reviewed, and spectrum analyses of BRCA1/2 mutation were assessed by systematic literature review. RESULTS: Frequency of BRCA1/2 mutations was 16.5% in KoOC patients. BRCA1/2 mutations were significantly associated with family history of breast/ovarian cancer (p<0.001), serous histology (p=0.044), and advanced International Federation of Gynecology and Obstetrics (FIGO) stage (III/IV, p=0.018) but not with early age-of-onset (age < 50, p=0.729). Literature review of BRCA1/2 mutations in KoOC patients found 111 (55 distinct) mutations with high proportion of Korean-specific mutations (24/55, 43.6%). Comparing the spectrum of BRCA1/2 mutation between KoOC and Korean breast cancer (KoBC) patients, the ratio of BRCA1-to-BRCA2 mutations was different, with BRCA1 (78.4%) being predominant in KoOC and BRCA2 in KoBC (59.2%). The most common mutation also differed between the two (c.3627insA of BRCA1 in KoOC and c.7480C>T of BRCA2 in KoBC). CONCLUSION: The clinical relevance of BRCA1/2 mutations in KoOC patients was confirmed but that of early age-of-onset was not. Possible inconsistency in the ratio of BRCA1-to-BRCA2 mutations and the most common mutation between KoOC and KoBC may probably suggest presence of mutation sequence-associated penetrance tendency in hereditary Korean breast and ovarian cancer. These data may provide insights for optimal genetic counseling and prophylactic treatment for at-risk relatives of KoOC patients.
Asian Continental Ancestry Group ; Breast ; Breast Neoplasms ; Genes, BRCA1 ; Genes, BRCA2 ; Genetic Counseling ; Germ-Line Mutation ; Gynecology ; Hospitals, University ; Humans ; Obstetrics ; Ovarian Neoplasms ; Penetrance ; Retrospective Studies

A number of specific genetic variants including gene mutations and single nucleotide variations have been identified in genomewide association studies of autism spectrum disorder (ASD). ASD phenotypes in individuals carrying specific genetic variations are manifest mostly in a heterozygous state. Furthermore, individuals with most genetic variants show incomplete penetrance and phenotypic variability, suggesting that non-genetic factors are also involved in developing ASD. However, the mechanisms of how genetic and environmental factors interactively promote ASD are not clearly understood. In the present study, we investigated whether early-life stress (ELS) in D2 dopamine receptor heterozygous knockout (D2(+/−)) mice induces ASD-like symptoms. To address that, we exposed D2 heterozygous pups to maternal separation stress for 3 h daily for 13 days beginning on postnatal day 2. D2(+/−) adult mice that had experienced ELS exhibited impaired sociability in the three-chamber test and home-cage social interaction test and increased grooming behavior, whereas wildtype littermates exposed to ELS did not show those phenotypes. ELS-exposed D2(+/−) mice had decreased levels of BDNF, TrkB, phospho-ERK1/2 and phospho-CREB in the dorsal striatum. Administration of the TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) to ELS-exposed D2(+/−) mice rescued the sociability deficits and repetitive behavior. In contrast, behavioral rescue by 7,8-DHF in ELS-exposed D2(+/−) mice was blocked when TrkB expression in the dorsal striatum was locally inhibited by the injection of TrkB-siRNA. Together, our results suggest that the interaction between ELS and defective D2 gene function promotes autistic-like behaviors by downregulating the BDNF-TrkB pathway in the dorsal striatum.
Adult ; Animals ; Autism Spectrum Disorder ; Brain-Derived Neurotrophic Factor ; Down-Regulation ; Genetic Variation ; Grooming ; Humans ; Interpersonal Relations ; Mice ; Penetrance ; Phenotype ; Receptor, trkB ; Receptors, Dopamine

BACKGROUND AND OBJECTIVES: To analyse the audiometric profile and the pedigree of a large family with otosclerosis to understand the inheritance pattern and its implication in clinical management of the disease. SUBJECTS AND METHODS: Pedigree analysis was performed on the basis of family history and audiometric tests. Pure tone audiometry, tympanometry, and acoustic reflexes were evaluated for the family members. Audiometric analysis was also carried out for the individuals who have already underwent corrective surgery at the time of study. RESULTS: Out of 112 family members, 17 were affected individuals, and 11 of them were surgically confirmed. Hearing loss (HL) started unilaterally and progressed to bilateral form. Otosclerosis was presented in early 20’s in the first and second generations but it was delayed to mid-late 30’s in the fourth generation. An affected female was diagnosed with otosclerosis during her pregnancy. Though the disease was familial, a mother of four affected offspring in this family did not develop otosclerosis until she died at the age of 84. CONCLUSIONS: The five-generation family, which was analysed in the present study, exhibited autosomal dominant inheritance of otosclerosis with reduced penetrance. Bilateral HL and pregnancy-aggravated otosclerosis were observed in this family. It was found for the first time that the age of onset of the disease delayed in the successive generations. The current study indicated the importance of detailed pedigree analysis for better clinical management of otosclerosis.
Acoustic Impedance Tests ; Age of Onset ; Audiometry ; Family Characteristics ; Female ; Hearing Loss ; Hearing Loss, Conductive ; Humans ; Inheritance Patterns ; Mothers ; Otosclerosis ; Pedigree ; Penetrance ; Pregnancy ; Reflex, Acoustic ; Wills

A 1q21.1 microdeletion is an extremely rare chromosomal abnormality that results in phenotypic diversity and incomplete penetrance. Patients with a 1q21.1 microdeletion exhibit neurological-psychiatric problems, microcephaly, epilepsy, facial dysmorphism, cataract, and thrombocytopenia absent radius syndrome. We reported a neonate with confirmed intrauterine growth restriction (IUGR), micrognathia, glossoptosis, upper airway obstruction, facial dysmorphism, and eye abnormality at birth as well as developmental delay at the age of 1 year. These clinical manifestations, except for the IUGR and upper airway obstruction, in the neonate indicated a 1q21.1 microdeletion. Here, we report a rare case of a 1q21.1 microdeletion obtained via paternal inheritance in a newborn with upper airway obstruction caused by glossoptosis and tracheal stenosis.
Airway Obstruction* ; Cataract ; Chromosome Aberrations ; Chromosome Deletion ; Epilepsy ; Eye Abnormalities ; Fetal Growth Retardation ; Glossoptosis ; Humans ; Infant, Newborn* ; Microarray Analysis ; Microcephaly ; Micrognathism ; Parturition ; Penetrance ; Radius ; Thrombocytopenia ; Tracheal Stenosis ; Wills

BACKGROUND: Autosomal-dominant brachydactyly type E is a congenital abnormality characterized by small hands and feet, which is a consequence of shortened metacarpals and metatarsals. We recently encountered a young gentleman exhibiting shortening of 4th and 5th fingers and toes. Initially, we suspected him having pseudopseudohypoparathyroidism (PPHP) because of normal biochemical parameters, including electrolyte, Ca, P, and parathyroid hormone (PTH) levels; however, his mother and maternal grandmother had the same conditions in their hands and feet. Furthermore, his mother showed normal biochemical parameters. To the best of our knowledge, PPHP is inherited via a mutated paternal allele, owing to the paternal imprinting of GNAS (guanine nucleotide binding protein, alpha stimulating) in the renal proximal tubule. Therefore, we decided to further analyze the genetic background in this family. METHODS: Whole exome sequencing was performed using genomic DNA from the affected mother, son, and the unaffected father as a negative control. RESULTS: We selected the intersection between 45,490 variants from the mother and 45,646 variants from the son and excluded 27,512 overlapping variants identified from the father. By excluding homogenous and compound heterozygous variants and removing all previously reported variants, 147 variants were identified to be shared by the mother and son. Variants that had least proximities among species were excluded and finally 23 variants remained. CONCLUSION: Among them, we identified a defect in parathyroid hormone like hormone (PTHLH), encoding the PTH-related protein, to be disease-causative. Herein, we report a family affected with brachydactyly type E2 caused by a novel PTHLH mutation, which was confused with PPHP with unclassical genetic penetrance.
Alleles ; Brachydactyly* ; Carrier Proteins ; Congenital Abnormalities ; DNA ; Exome ; Fathers ; Fingers ; Foot ; Genetic Background ; Grandparents ; Hand ; Humans ; Metacarpal Bones ; Metatarsal Bones ; Mothers ; Parathyroid Hormone ; Parathyroid Hormone-Related Protein ; Penetrance ; Pseudopseudohypoparathyroidism* ; Toes

Pathogenic variants of bone morphogenic protein receptor type 2 gene (BMPR2) are related to the majority of cases of heritable pulmonary arterial hypertension (PAH). Over 400 pathogenic variants have been identified. However, clinical characterization of PAH is still incomplete. We present a case of heritable PAH in a Korean family showing serious clinical presentation with high penetrance. Genetic sequencing revealed a known heterozygous BMPR2 pathogenic variant, c.418+5G>A, at a splice site of intron 3. Serious clinical presentation with high penetrance suggested that the interplay of other factors with pathologic variants might be in genotype-phenotype correlation. Further studies are needed to clarify these issues for the development of personalized medicine approaches for PAH.
Familial Primary Pulmonary Hypertension ; Genetic Association Studies ; Humans ; Hypertension* ; Hypertension, Pulmonary ; Introns* ; Penetrance* ; Precision Medicine ; Pulmonary Artery

OBJECTIVE: Diagnosis of sporadic cerebellar ataxia is a challenge for neurologists. A wide range of potential causes exist, including chronic alcohol use, multiple system atrophy of cerebellar type (MSA-C), and sporadic late cortical cerebellar atrophy. Recently, an autosomal-dominant spinocerebellar ataxia (SCA) mutation was identified in a cohort of patients with non-MSA-C sporadic cerebellar ataxia. The aim of this study is to genetically screen genes involved in SCA in a Japanese single-hospital cohort. METHODS: Over an 8-year period, 140 patients with cerebellar ataxia were observed. There were 109 patients with sporadic cerebellar ataxia (no family history for at least four generations, 73 patients with MSA-C, and 36 patients with non-MSA-C sporadic cerebellar ataxia) and 31 patients with familial cerebellar ataxia. We performed gene analysis comprising SCA1, 2, 3, 6, 7, 8, 12, 17, 31, and dentatorubro-pallidoluysian atrophy (DRPLA) in 28 of 31 non-MSA-C sporadic patients who requested the test. Familial patients served as a control. RESULTS: Gene abnormalities were found in 57% of non-MSA-C sporadic cerebellar ataxia cases. Among patients with sporadic cerebellar ataxia, abnormalities in SCA6 were the most common (36%), followed by abnormalities in SCA1 (7.1%), SCA2 (3.6%), SCA3 (3.6%), SCA8 (3.6%), and DRPLA (3.6%). In contrast, gene abnormalities were found in 75% of familial cerebellar ataxia cases, with abnormalities in SCA6 being the most common (29%). For sporadic versus familial cases for those with SCA6 abnormalities, the age of onset was older (69 years vs. 59 years, respectively), and CAG repeat length was shorter (23 vs. 25, respectively) in the former than in the latter (not statistically significant). CONCLUSION: Autosomal-dominant mutations in SCA genes, particularly in SCA6, are not rare in sporadic cerebellar ataxia. The reason for the frequency of mutations in SCA6 remains unclear; however, the reason may reflect a higher age at onset and variable penetrance of SCA6 mutations.
Age of Onset ; Asian Continental Ancestry Group* ; Atrophy ; Cerebellar Ataxia ; Cohort Studies* ; Diagnosis ; Family Characteristics ; Genetic Testing* ; Heredity ; Humans ; Multiple System Atrophy ; Penetrance ; Spinocerebellar Ataxias*

Pancreatic cancer (PC) is the third most common cause of cancer-related death in the United States and the 12th most common worldwide. Mortality is high, largely due to late stage of presentation and suboptimal treatment regimens. Approximately 10% of PC cases have a familial basis. The major genetic defect has yet to be identified but may be inherited by an autosomal dominant pattern with reduced penetrance. Several known hereditary syndromes or genes are associated with an increased risk of developing PC and account for approximately 2% of PCs. These syndromes include the hereditary breast-ovarian cancer syndrome, Peutz-Jeghers syndrome, familial atypical multiple mole melanoma, Lynch syndrome, familial polyposis, ataxia-telangiectasia, and hereditary pancreatitis. Appropriate screening using methods such as biomarkers or imaging, with endoscopic ultrasound and magnetic resonance imaging, may assist in the early detection of neoplastic lesions in the high-risk population. If these lesions are detected and treated before the development of invasive carcinoma, PC disease morbidity and mortality may be improved. This review will focus on familial PC and other hereditary syndromes implicated in the increased risk of PC; it will also highlight current screening methods and the future of new screening modalities.
Ataxia Telangiectasia ; Biomarkers ; Colorectal Neoplasms, Hereditary Nonpolyposis ; Dysplastic Nevus Syndrome ; Magnetic Resonance Imaging ; Mass Screening* ; Mortality ; Pancreatic Neoplasms* ; Pancreatitis ; Penetrance ; Peutz-Jeghers Syndrome ; Ultrasonography ; United States

STUDY DESIGN: Prospective case-controlled study. PURPOSE: This study aimed to assess genetic influence in Saudi Arabian children with adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: The genetic locus linked to chromosome 19p for idiopathic scoliosis has been described. A pilot study conducted at King Fahd Hospital of the University, Al-Khobar showed that three microsatellite markers (D19S216, D19S894, and DS1034) of chromosome 19p13.3 were significant in Saudi Arabian females compared with healthy subjects. METHODS: A total of 100 unrelated Saudi Arabian girls treated for AIS, their parents, healthy siblings, and healthy subjects were recruited for genetic analysis of markers on chromosome 19p13.3. After informed consent was obtained from their parents, blood samples were collected and parametric and nonparametric linkage analyses were performed using GENEHUNTER ver. 2.1. Multipoint linkage analysis was used to specify an autosomal dominant trait with a gene frequency of 0.01 and an estimated penetrance of 80% at the genotypic and allelic levels. RESULTS: Five hundred blood samples were collected and analyzed for microsatellite markers (D19S216, D19S894, and DS1034) of chromosome 19p13.3. Comparison among patients, family members, and healthy subjects revealed no significant association between markers and scoliosis at the genotypic level: D19S216 (p=0.21), D19S894 (p=0.37), and DS1034 (p=0.25). However, at the allelic level, a statistically significant association was observed for marker DS1034 (p=0.008), and marker D19S216 showed significance between fathers and patients (p<0.001) compared with patients and mothers. The other two markers, D19S216 (p=0.25) and D19S894 (p=0.17), showed no significant association between patients and mothers. CONCLUSIONS: At the allelic level, marker DS1034 was significantly associated with AIS patients and their fathers. This allelic marker on chromosome 19p13.3 appears to be important in AIS etiology.
Adolescent* ; Case-Control Studies ; Child ; Fathers ; Female* ; Genes, vif ; Genetic Loci ; Genetic Markers* ; Healthy Volunteers ; Humans ; Informed Consent ; Microsatellite Repeats ; Mothers ; Parents ; Penetrance ; Pilot Projects ; Prospective Studies ; Saudi Arabia ; Scoliosis* ; Siblings