Risk Factors of Preterm Birth in Okinawa Prefecture, the Southernmost Island Prefecture of Japan.

OBJECTIVES: A high rate of preterm birth has been reported in Okinawa Prefecture, the southernmost island prefecture of Japan. Hence, this study aimed to identify the risk factors for preterm birth in this prefecture. METHODS: This retrospective study included data from January 2013 to December 2019 from three facilities in Okinawa Prefecture. Of 13,468 cases of preterm birth at ≥ 22 weeks of gestation, 11,868 were included in this study. Stillbirth and multiparity cases were excluded. First, we compared the overall preterm and full-term birth groups by categorizing the patient background, obstetric, and fetal risk factors. Further, we categorized preterm births into three groups (22-27, 28-33, and 34-36 weeks of gestation) and examined patient background factors to identify potential risk factors for the occurrence of preterm birth in each group. RESULTS: Preterm births accounted for 21.2% (2,521 cases) of all cases, with the rates of 2.6% (317 cases), 6.7% (800 cases), and 11.8% (1,404 cases) at 22-27, 28-33, and 34-36 weeks of gestation, respectively. To prevent preterm birth in Okinawa Prefecture, the present study specifically focused on patient background characteristics. In the multinomial logistic regression, the risk factors for preterm birth at 22-27 weeks of gestation were previous preterm birth (P < 0.0001) and lower age (P = 0.026); at 28-33 weeks of gestation, the risk factors were previous preterm birth (P < 0.0001) and history of cervical conization (P = 0.009); and at 34-36 weeks of gestation, only previous preterm birth (P < 0.0001) was a risk factor. CONCLUSIONS FOR PRACTICE: Previous preterm birth, younger age, and history of cervical conization were risk factors for Preterm birth in Okinawa. To reduce premature births in Okinawa Prefecture, it is important to pick up women with these risk factors and provide them with appropriate guidance and education on an ongoing basis.

Genetic association analysis of 77,539 genomes reveals rare disease etiologies.

The genetic etiologies of more than half of rare diseases remain unknown. Standardized genome sequencing and phenotyping of large patient cohorts provide an opportunity for discovering the unknown etiologies, but this depends on efficient and powerful analytical methods. We built a compact database, the 'Rareservoir', containing the rare variant genotypes and phenotypes of 77,539 participants sequenced by the 100,000 Genomes Project. We then used the Bayesian genetic association method BeviMed to infer associations between genes and each of 269 rare disease classes assigned by clinicians to the participants. We identified 241 known and 19 previously unidentified associations. We validated associations with ERG, PMEPA1 and GPR156 by searching for pedigrees in other cohorts and using bioinformatic and experimental approaches. We provide evidence that (1) loss-of-function variants in the Erythroblast Transformation Specific (ETS)-family transcription factor encoding gene ERG lead to primary lymphoedema, (2) truncating variants in the last exon of transforming growth factor-ß regulator PMEPA1 result in Loeys-Dietz syndrome and (3) loss-of-function variants in GPR156 give rise to recessive congenital hearing impairment. The Rareservoir provides a lightweight, flexible and portable system for synthesizing the genetic and phenotypic data required to study rare disease cohorts with tens of thousands of participants.

Molecular and clinical analysis of RAF1 in Noonan syndrome and related disorders: dephosphorylation of serine 259 as the essential mechanism for mutant activation.

Noonan syndrome (NS) and related disorders are autosomal dominant disorders characterized by heart defects, facial dysmorphism, ectodermal abnormalities, and mental retardation. The dysregulation of the RAS/MAPK pathway appears to be a common molecular pathogenesis of these disorders: mutations in PTPN11, KRAS, and SOS1 have been identified in patients with NS, those in KRAS, BRAF, MAP2K1, and MAP2K2 in patients with CFC syndrome, and those in HRAS mutations in Costello syndrome patients. Recently, mutations in RAF1 have been also identified in patients with NS and two patients with LEOPARD (multiple lentigines, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormal genitalia, retardation of growth, and sensorineural deafness) syndrome. In the current study, we identified eight RAF1 mutations in 18 of 119 patients with NS and related conditions without mutations in known genes. We summarized clinical manifestations in patients with RAF1 mutations as well as those in NS patients withPTPN11, SOS1, or KRAS mutations previously reported. Hypertrophic cardiomyopathy and short stature were found to be more frequently observed in patients with RAF1 mutations. Mutations in RAF1 were clustered in the conserved region 2 (CR2) domain, which carries an inhibitory phosphorylation site (serine at position 259; S259). Functional studies revealed that the RAF1 mutants located in the CR2 domain resulted in the decreased phosphorylation of S259, and that mutant RAF1 then dissociated from 14-3-3, leading to a partial ERK activation. Our results suggest that the dephosphorylation of S259 is the primary pathogenic mechanism in the activation of RAF1 mutants located in the CR2 domain as well as of downstream ERK.

Physicians' opinion for 'new' genetic testing in Japan.

Recent advances in studies on human genetics have led to the use of genetic information in various applications. We conducted a survey to know the opinions of healthcare providers in Japan on new genetic testing services, such as direct-to-consumer (DTC) genetic testing. A total of 1124 general practitioners and 294 clinical geneticists replied to our questionnaire. Thirty-eight percent of the general practitioners and 68.4% of the clinical geneticists were aware of DTC genetic testing. Some physicians had gained information on this service through their patients or commercial activities of companies providing such services. General practitioners expected that DTC genetic testing would be convenient, promote preventive medicine, provide personalized services and would enable to maintain confidentiality of information. Clinical geneticists showed greater concern with regard to the reliability of the results, provision of information/counseling and the understanding of results. Awareness of DTC genetic testing enhances general practitioners' positive opinions of it. Although the market for DTC genetic testing in Japan may still be limited, it is possible that general practitioners will play a role in the provision of DTC genetic testing services in the future. On the basis of their knowledge and experience, clinical geneticists should provide information to both healthcare providers and to the public.

Severity and progression rate of cerebellar ataxia in 16q-linked autosomal dominant cerebellar ataxia (16q-ADCA) in the endemic Nagano Area of Japan.

16q22.1-linked autosomal dominant cerebellar ataxia (16q-ADCA) is a recently defined subtype of ADCA identified by a disease-specific C/T substitution in the 5' untranslated region of the puratrophin-1 gene. In Nagano, the central mountainous district of the main island of Japan, 16q-ADCA and spinocerebellar ataxia type 6 (SCA6) are the most and second most prevalent subtypes of ADCA, respectively. Both subtypes are classified into Harding's ADCA III, but little attention has been given to the differences in the severity and progression rate of cerebellar ataxia between 16q-ADCA and SCA6. We investigated the clinical severity and progression rate of cerebellar ataxia of 16q-ADCA patients using international cooperative ataxia rating scale and scale for the assessment and rating of ataxia and compared them with those of SCA6 patients. The age at onset was much higher in 16q-ADCA patients (60.1 +/- 9.8 years, n = 66) than in SCA6 patients (41.1 +/- 8.7 years, n = 35). Clinical features of 16q-ADCA were basically consistent with pure cerebellar ataxia, as well as in SCA6, but gaze-evoked nystagmus was observed less frequently in 16q-ADCA patients than in SCA6 patients. When compared at almost the same disease duration after onset, the severity of cerebellar ataxia was a little higher, and the progression rate seemed more rapid in 16q-ADCA patients than in SCA6 patients, but the differences were not significant.

[Survey on the attitude toward genetic testing of neurologists certified by the Japanese Society of Neurology].

To clarify the attitude toward genetic testing for neuromuscular diseases, a questionnaire was sent to 4,762 neurologists certified by the Japanese Society of Neurology. By December 21, 2011, 1,493 questionnaires (31.4%) were returned. Of these, 1,233 (82.6%) had experienced genetic testing, but only 396 (26.5%) had referred to the guideline for genetic testing of the Japanese Society of Neurology (2009). The numbers of respondents who were positive, or more positive than negative for genetic testing for myotonic dystrophy type 1 (DM1), Huntington's disease (HD), and familial amyloid polyneuropathy (FAP) were 753 (50.4%), 915 (61.3%), and 980 (65.6%), respectively. The predominant reason for a positive attitude toward genetic testing was to confirm or exclude the diagnosis. Conversely, the predominant reason for a negative attitude toward genetic testing differed between the diseases. For DM1, it was to confirm the diagnosis without genetic testing. For HD, it was that genetic testing would not result in effective prevention or therapy. In FAP, it was that post-testing psychosocial support for the patient and their family was difficult. Common to DM1, HD, and FAP, a significant number of respondents (approximately 60%) felt it difficult to explain the negative aspects that might occur after the disclosure of test results. Concerning predictive or prenatal genetic testing, most respondents referred at-risk individuals to specialized genetic counseling clinics. In general, neurologists are likely to conduct genetic testing properly in consideration not only of the characteristics of the diseases but also of the circumstances of each patient and his or her family. To support neurologists who are involved in genetic testing, the guidelines should be more easily accessible. Many respondents wanted information on the institutions that provide genetic counseling and testing; however, financial support to such institutions is indispensable for fulfilling this requirement.

FBN2, FBN1, TGFBR1, and TGFBR2 analyses in congenital contractural arachnodactyly.

FBN2, FBN1, TGFBR1, and TGFBR2 were analyzed by direct sequencing in 15 probands with suspected congenital contractural arachnodactyly (CCA). A total of four novel FBN2 mutations were found in four probands (27%, 4/15), but remaining the 11 did not show any abnormality in either of the genes. This study indicated that FBN2 mutations were major abnormality in CCA, and TGFBR and FBN1 defects may not be responsible for the disorder. FBN2 mutations were only found at introns 30, 31, and 35 in this study. Thus analysis of a mutational hotspot from exons 22 to 36 (a middle part) of FBN2 should be prioritized in CCA as previously suggested.

Complete hydatidiform mole and normal live birth following intracytoplasmic sperm injection.

A twin pregnancy with complete hydatidiform mole (HM) and preterm birth of a normal female infant after intracytoplasmic sperm injection (ICSI) conception was experienced. ICSI due to severe oligozoospermia was performed on three ova, and three embryos with confirmed two proneclei (2PN) were subsequently transferred to the uterus. At 7 weeks of gestation, molar pregnancy as well as a viable fetus was recognized. At 33 weeks, the pregnancy was terminated due to preterm labor. Dichorionic pregnancy consisting of a normal fetus and placenta in one chorionic membrane and complete HM in the other was recognized. Cytomolecular analysis indicated that the complete HM genome was derived from duplication of a single sperm, and a normal neonate was from biparental genomes. It should be noted that ICSI can avoid incomplete HM (mostly triploid) due to multi-sperm fertilization but might not be able to avoid complete HM (paternal diploid) although such a risk is very low. This is the second report of this condition and is accompanied by the first well-described molecular analysis.

A -16C>T substitution in the 5' UTR of the puratrophin-1 gene is prevalent in autosomal dominant cerebellar ataxia in Nagano.

The molecular bases of autosomal dominant cerebellar ataxia (ADCA) have been increasingly elucidated, but 17-50% of ADCA families still remain genetically undefined in Japan. In this study we investigated 67 genetically undefined ADCA families from the Nagano prefecture, and found that 63 patients from 51 families possessed the -16C>T change in the puratrophin-1 gene, which was recently found to be pathogenic for 16q22-linked ADCA. Most patients shared a common haplotype around the puratrophin-1 gene. All patients with the -16C>T change had pure cerebellar ataxia with middle-aged or later onset. Only one patient in a large, -16C>T positive family did not have this change, but still shared a narrowed haplotype with, and was clinically indistinguishable from, the other affected family members. In Nagano, 16q22-linked ADCA appears to be much more prevalent than either SCA6 or dentatorubral-pallidoluysian atrophy (DRPLA), and may explain the high frequency of spinocerebellar ataxia.