Dyssegmental dysplasia Rolland-Desbuquois type is caused by pathogenic variants in HSPG2 - a founder haplotype shared in five patients.

Dyssegmental dysplasia (DD) is a severe skeletal dysplasia comprised of two subtypes: lethal Silverman-Handmaker type (DDSH) and nonlethal Rolland-Desbuquois type (DDRD). DDSH is caused by biallelic pathogenic variants in HSPG2 encoding perlecan, whereas the genetic cause of DDRD remains undetermined. Schwartz-Jampel syndrome (SJS) is also caused by biallelic pathogenic variants in HSPG2 and is an allelic disorder of DDSH. In SJS and DDSH, 44 and 8 pathogenic variants have been reported in HSPG2, respectively. Here, we report that five patients with DDRD carried four pathogenic variants in HSPG2: c.9970 G > A (p.G3324R), c.559 C > T (p.R187X), c7006 + 1 G > A, and c.11562 + 2 T > G. Two patients were homozygous for p.G3324R, and three patients were heterozygous for p.G3324R. Haplotype analysis revealed a founder haplotype spanning 85,973 bp shared in the five patients. SJS, DDRD, and DDSH are allelic disorders with pathogenic variants in HSPG2.

Prenatal diagnosis of bone dysplasias.

Bone dysplasias are individually rare but collectively common. The prenatal diagnosis of bone dysplasias, especially perinatally lethal dysplasias, is of major interest to obstetric services. The current nosology of genetic skeletal disorders addresses over 400 disorders. However, in clinical practice, we encounter only a limited number of disorders, such as FGFR3-related dysplasias, osteogenesis imperfecta, and type II collagenopathies. The recent development of non-invasive prenatal genetic testing using cell-free fetal DNA in maternal blood samples has had a major impact on the prenatal diagnosis of genetic diseases. However, imaging examinations remain critical for the final diagnosis of bone dysplasias because molecular testing only shows genetic variants, and not their pathogenicity - most variants are clinically insignificant. Bone dysplasias are typically suspected when limb shortening is identified by screening ultrasound. Further assessment can be followed by more detailed ultrasound, magnetic resonance imaging (MRI), and CT. Based on these data, rational decision-making is feasible, even when the definitive prenatal diagnosis is not feasible. Here, we highlight key images of common bone dysplasias obtained by currently available modalities.

Estimation of the carrier frequencies and proportions of potential patients by detecting causative gene variants associated with autosomal recessive bone dysplasia using a whole-genome reference panel of Japanese individuals.

Bone dysplasias are a group of rare hereditary diseases, with up to 436 disease types. Perinatal diagnosis is clinically important for adequate personalized management and counseling. There are no reports focused on pathogenic variants of bone dysplasias in the general population. In this study, we focused on autosomal recessive bone dysplasias. We identified pathogenic variants using whole-genome reference panel data from 3552 Japanese individuals. For the first time, we were able to estimate the carrier frequencies and the proportions of potential patients. For autosomal recessive bone dysplasias, we detected 198 pathogenic variants of 54 causative genes. We estimated the variant carrier frequencies and the proportions of potential patients with variants associated with four clinically important bone dysplasias: osteogenesis imperfecta (OI), hypophosphatasia (HPP), asphyxiating thoracic dysplasia (ATD), and Ellis-van Creveld syndrome (EvC). The proportions of potential patients with OI, ATD, and EvC based on pathogenic variants classified as "pathogenic" and "likely pathogenic" by InterVar were closer to the reported incidence rates in Japanese subjects. Furthermore, the proportions of potential patients with HPP variants classified as "pathogenic" and "likely pathogenic" in InterVar and "pathogenic" in ClinVar were closer to the reported incidence rates. For bone dysplasia, the findings of this study will provide a better understanding of the variant types and frequencies in the Japanese general population, and should be useful for clinical diagnosis, genetic counseling, and personalized medicine.

Prenatal sonographic findings and prognosis of craniosynostosis diagnosed during the fetal and neonatal periods.

The aim of the study was to explore the sonographic findings of fetuses with craniosynostosis and investigate their prognosis. We conducted a 5-year, multicenter retrospective study and collected data on patients with craniosynostosis diagnosed in the perinatal period. Of 41 cases, 30 cases (73%) were syndromic craniosynostosis, eight cases (20%) were non-syndromic craniosynostosis and the other three cases (7%) were secondary craniosynostosis of chromosomal deletion syndromes. The prenatal ultrasound detection rate was 61%. Half of the cases of syndromic craniosynostosis detected during the perinatal period were Pfeiffer syndrome; there were also six cases of Apert syndrome, three cases of Crouzon syndrome and other rare form of syndromic craniosynostosis (Beare-Stevenson syndrome, Saethre-Chotzen syndrome, cranioectodermal dysplasia, and thanatophoric dysplasia). Abnormal shape of the skull was the most common finding leading to prenatal diagnosis of craniosynostosis. Abnormal head biometry, which was the second most frequent finding, was closely correlated with deformation of the cranial shape. Three cases presented with ventriculomegaly and exophthalmos but normal cranial shape and size. The overall survival rate of infants with syndromic craniosynostosis was 79%, while all of the infants with non-syndromic craniosynostosis survived. In conclusion, prenatal diagnosis of craniosynostosis is difficult, especially when dysmorphic change of the fetal cranium is not evident. Abnormal head biometry and ventriculomegaly could potentially be additional markers of fetal craniosynostosis and consequently increase the prenatal detection rate.

Differential diagnosis of perinatal hypophosphatasia: radiologic perspectives.

Perinatal hypophosphatasia (HPP) is a rare, potentially life-threatening, inherited, systemic metabolic bone disease that can be difficult to recognize in utero and postnatally. Diagnosis is challenging because of the large number of skeletal dysplasias with overlapping clinical features. This review focuses on the role of fetal and neonatal imaging modalities in the differential diagnosis of perinatal HPP from other skeletal dysplasias (e.g., osteogenesis imperfecta, campomelic dysplasia, achondrogenesis subtypes, hypochondrogenesis, cleidocranial dysplasia). Perinatal HPP is associated with a broad spectrum of imaging findings that are characteristic of but do not occur in all cases of HPP and are not unique to HPP, such as shortening, bowing and angulation of the long bones, and slender, poorly ossified ribs and metaphyseal lucencies. Conversely, absent ossification of whole bones is characteristic of severe lethal HPP and is associated with very few other conditions. Certain features may help distinguish HPP from other skeletal dysplasias, such as sites of angulation of long bones, patterns of hypomineralization, and metaphyseal characteristics. In utero recognition of HPP allows for the assembly and preparation of a multidisciplinary care team before delivery and provides additional time to devise treatment strategies.

New terminology for adverse events of fetal therapy: Re-evaluation of the thoraco-amniotic shunting in a Japanese study.

AIM: Since fetal therapy has been newly developed, objective evaluation of adverse events (AE), all harmful events that are not always related to the procedures, has not yet been adequately reported. We established new terminology and tried to re-evaluate it based on the Japanese prospective thoraco-amniotic shunting (TAS) study. METHODS: From the literature, all complications that occurred with all fetal therapies were identified as a basis for developing the terminology. Grading was set from 0 to 5. Grade 3 was defined as the need for invasive treatment, such as surgery. Grade 4 was defined as life-threatening, and Grade 5 was defined as death of the mother or fetus. Then, one series of TAS that we had already reported was re-evaluated, including 24 cases with 37 procedures and 200 opportunities those could be evaluated AE after procedures. RESULTS: Grade 4 preterm rupture of the membranes was reported in only 1 of 24 cases. Catheter displacement was reported in 7, 2 and 11 cases, of Grades 1, 2 and 3, respectively. It was found that the double-basket catheter had some association with catheter displacement, but it was clear that there were no life-threatening AE. CONCLUSION: Newly developed AE criteria are now available for fetal therapy. They will contribute to the objective evaluation of AE of new fetal therapies in the future.

Classification of factors involved in nonreportable results of noninvasive prenatal testing (NIPT) and prediction of success rate of second NIPT.

OBJECTIVE: To evaluate the reasons for nonreportable cell-free DNA (cfDNA) results in noninvasive prenatal testing (NIPT), we retrospectively studied maternal characteristics and other details associated with the results. METHODS: A multicenter retrospective cohort study in pregnant women undergoing NIPT by massively parallel sequencing (MPS) with failed cfDNA tests was performed between April 2013 and March 2017. The women's data and MPS results were analyzed in terms of maternal characteristics, test performance, fetal fraction (FF), z scores, anticoagulation therapy, and other details of the nonreportable cases. RESULTS: Overall, 110 (0.32%) of 34 626 pregnant women had nonreportable cfDNA test results after an initial blood sampling; 22 (20.0%) cases had a low FF (<4%), and 18 (16.4%) cases including those with a maternal malignancy, were found to have altered genomic profile. Approximately half of the cases with nonreportable results had borderline z score. Among the women with nonreportable results because of altered genomic profile, the success rate of retesting using a second blood sampling was relatively low (25.0%-33.3%). Thirteen (11.8%) of the women with nonreportable results had required hypodermic heparin injection. CONCLUSIONS: The classification of nonreportable results using cfDNA analysis is important to provide women with precise information and to reduce anxiety during pregnancy.

A novel mutation in the C-propeptide of COL2A1 causes atypical spondyloepiphyseal dysplasia congenita.

Spondyloepiphyseal dysplasia congenita (SEDC, OMIM #183900) is one of the type II collagenopathies caused by a heterozygous mutation in the COL2A1 gene. Although typical SEDC shows delay of pubic bone ossification on radiographs, atypical SEDC exists without this finding. We identified an atypical SEDC patient with a novel missense mutation in the C-propeptide region of COL2A1. This case suggests that a COL2A1 C-propeptide mutation can cause atypical SEDC.

Parental serum alkaline phosphatase activity as an auxiliary tool for prenatal diagnosis of hypophosphatasia.

OBJECTIVE: The objective of this study is to clarify the usefulness of parental alkaline phosphatase (ALP) for prenatal diagnosis of hypophosphatasia (HPP). METHODS: Maternal (m) and paternal (p) ALP values were measured in 77 cases from a multicenter cohort (fetal skeletal dysplasia forum in Japan) of cases with short limbs on ultrasonography during pregnancy. After birth, X-rays, cord blood ALP, and gene analysis were evaluated to achieve an exact diagnosis. The screening usefulness of ALP was examined retrospectively. RESULTS: Seventeen cases were eventually diagnosed as HPP and 60 as not HPP; the overall mean m-ALP and p-ALP (standard deviation) values were 133.4 (53) versus 197 (69) IU/L and 149.6 (71.8) versus 231 (61.4) IU/L (p < 0.001). Receiver operating characteristic curve analysis showed that the optimal m-ALP and p-ALP cutoff values were 123 and 165 IU/L, respectively. Presence of at least one of the m-ALP or p-ALP values abnormally low had a sensitivity, specificity, and positive predictive values of 82% (14/17), 93%, and 78%, respectively, for the diagnosis of HPP. CONCLUSION: Parental ALP measurement might be an auxiliary tool to hone in the prenatal diagnosis of fetal HPP. © 2017 John Wiley & Sons, Ltd.

Follow-Up Study on Fetal CT Radiation Dose in Japan: Validating the Decrease in Radiation Dose.

OBJECTIVE: In 2011, we collected data on fetal CT radiation dose to determine the diagnostic reference level (DRL); however, continuous evaluation of the DRL is necessary. The hypothesis of this study is that the fetal CT radiation dose has decreased, and we predict a widespread use of iterative reconstruction (IR). We also predict that the national decrease in exposure is because of the DRL reported as a result of the previous national study. MATERIALS AND METHODS: Various testing protocols from each site were summarized as part of the study results. The minimum, one-fourth (25th percentile), median, three-fourths (75th percentile), and maximum values were obtained for volume CT dose index (CTDIvol), dose-length product (DLP), and scan length of 120 fetal CT examinations. The trends for IR usage and tube voltage were also investigated. RESULTS: Compared to the results of the 2011 study (n = 119), the minimum, 25th percentile, median, and 75th percentile values for CTDIvol and DLP have decreased for the tabulated results in 2015 (n = 120). The 75th percentile value for CTDIvol was 4.9 mGy, which is 43% of the previous value. IR was used in 70% of the sites. The radiation dose was significantly lower among groups that used IR. CONCLUSION: Four years passed between our initial survey on DRL and the present follow-up survey, and it appears that the previous report sufficiently fulfilled its objective and role in contributing to the decrease in DRL observed in this follow-up study.

Factors affecting parental decisions to terminate pregnancy in the presence of chromosome abnormalities: a Japanese multicenter study.

OBJECTIVE: To investigate the rates of termination of pregnancy (TOP) for fetal chromosomal abnormalities and factors related to such parental decision in Japan. METHODS: A multicenter retrospective cohort study of chromosomal abnormalities diagnosed before 22 weeks of gestation between April 2008 and March 2015. The pregnancy outcomes and parental decisions were investigated. RESULTS: Among 931 fetuses with chromosome abnormalities, the total TOP rate was 75.1% (699/931). TOP rates were 89.3% (585/655) in autosomal aneuploidies and 40.8% (51/125) in sex chromosome aneuploidies. Trisomy 21 showed the highest TOP rate (93.8% [390/416]) followed by trisomy 18 (84.5% [163/193]) and trisomy 13 (71.9% [23/32]). Indications for karyotyping were related to a parental decision for TOP (p < 0.01): in cases of autosomal aneuploidy, with fetal abnormal ultrasound findings as the reference value, diagnoses made following positive results at non-invasive prenatal testing (adjusted odds ratio [OR]: 13.7, 95% confidence interval [CI] 4.07-45.9) and those because of advanced maternal age (adj. OR 2.91, 95% CI 1.15-7.35) were significantly more frequent. CONCLUSIONS: In Japan, pregnancies with fetal trisomy 21 are more likely to result in TOP when diagnosed in utero than any other chromosome anomaly. The indications for prenatal karyotyping strongly affect the decision to TOP. © 2016 John Wiley & Sons, Ltd.

Association of achondroplasia with Down syndrome: difficulty in prenatal diagnosis by sonographic and 3-D helical computed tomographic analyses.

Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome.

Diagnosis and Treatment of a Preterm Infant With Inoperable Congenital Hepatoblastoma--A Case Report.

Reports of hepatoblastoma (HB) in preterm infants are quite rare. Herein, we report the clinical management of a preterm infant with inoperable congenital HB. A female fetus that had been diagnosed with a large liver tumor consistent with hemangioma was delivered by emergency cesarean section at 33 weeks of gestation because of fetal distress. Effective antitumor therapy could not be performed, resulting in rapid deterioration and death. The postmortem histopathologic analysis confirmed the tumor as a HB. This report demonstrates the difficulties inherent in both the image diagnosis of HB and in providing efficacious treatments for preterm infants with HB.

Modeling type II collagenopathy skeletal dysplasia by directed conversion and induced pluripotent stem cells.

Type II collagen is a major component of cartilage. Heterozygous mutations in the type II collagen gene (COL2A1) result in a group of skeletal dysplasias known as Type II collagenopathy (COL2pathy). The understanding of COL2pathy is limited by difficulties in obtaining live chondrocytes. In the present study, we converted COL2pathy patients' fibroblasts directly into induced chondrogenic (iChon) cells. The COL2pathy-iChon cells showed suppressed expression of COL2A1 and significant apoptosis. A distended endoplasmic reticulum (ER) was detected, thus suggesting the adaptation of gene expression and cell death caused by excess ER stress. Chondrogenic supplementation adversely affected the chondrogenesis due to forced elevation of COL2A1 expression, suggesting that the application of chondrogenic drugs would worsen the disease condition. The application of a chemical chaperone increased the secretion of type II collagen, and partially rescued COL2pathy-iChon cells from apoptosis, suggesting that molecular chaperons serve as therapeutic drug candidates. We next generated induced pluripotent stem cells from COL2pathy fibroblasts. Chondrogenically differentiated COL2pathy-iPS cells showed apoptosis and increased expression of ER stress-markers. Finally, we generated teratomas by transplanting COL2pathy iPS cells into immunodeficient mice. The cartilage in the teratomas showed accumulation of type II collagen within cells, a distended ER, and sparse matrix, recapitulating the patient's cartilage. These COL2pathy models will be useful for pathophysiological studies and drug screening.

Guidelines for obstetrical practice in Japan: Japan Society of Obstetrics and Gynecology (JSOG) and Japan Association of Obstetricians and Gynecologists (JAOG) 2014 edition.

The 'Clinical Guidelines for Obstetrical Practice, 2011 edition' were revised and published as a 2014 edition (in Japanese) in April 2014 by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists. The aims of this publication include the determination of current standard care practices for pregnant women in Japan, the widespread use of standard care practices, the enhancement of safety in obstetrical practice, the reduction of burdens associated with medico-legal and medico-economical problems, and a better understanding between pregnant women and maternity-service providers. The number of Clinical Questions and Answers items increased from 87 in the 2011 edition to 104 in the 2014 edition. The Japanese 2014 version included a Discussion, a List of References, and some Tables and Figures following the Answers to the 104 Clinical Questions; these additional sections covered common problems and questions encountered in obstetrical practice, helping Japanese readers to achieve a comprehensive understanding. Each answer with a recommendation level of A, B or C was prepared based principally on 'evidence' or a consensus among Japanese obstetricians in situations where 'evidence' was weak or lacking. Answers with a recommendation level of A or B represent current standard care practices in Japan. All 104 Clinical Questions and Answers items, with the omission of the Discussion, List of References, and Tables and Figures, are presented herein to promote a better understanding among English readers of the current standard care practices for pregnant women in Japan.

Nationwide radiation dose survey of computed tomography for fetal skeletal dysplasias.

BACKGROUND: Recently, computed tomography (CT) has been used to diagnose fetal skeletal dysplasia. However, no surveys have been conducted to determine the radiation exposure dose and the diagnostic reference level (DRL). OBJECTIVE: To collect CT dose index volume (CTDIvol) and dose length product (DLP) data from domestic hospitals implementing fetal skeletal 3-D CT and to establish DRLs for Japan. MATERIALS AND METHODS: Scan data of 125 cases of 20 protocols from 16 hospitals were analyzed. The minimum, first-quartile, median, third-quartile and maximum values of CTDIvol and DLP were determined. The time-dependent change in radiation dose setting in hospitals with three or more cases with scans was also examined. RESULTS: The minimum, first-quartile, median, third-quartile and maximum CTDIvol values were 2.1, 3.7, 7.7, 11.3 and 23.1 mGy, respectively, and these values for DLP were 69.0, 122.3, 276.8, 382.6 and 1025.6 mGy·cm, respectively. Six of the 12 institutions reduced the dose setting during the implementation period. CONCLUSIONS: The DRLs of CTDIvol and DLP for fetal CT were 11.3 mGy and 382.6 mGy·cm, respectively. Institutions implementing fetal CT should use these established DRLs as the standard and make an effort to reduce radiation exposure by voluntarily decreasing the dose.

[Fetal therapy of skeletal dysplasias].

Three types of fetal therapy of skeletal dysplasias, as enzyme replacement, in utero stem cell transplantation, and gene therapy, are reviewed. Clinical trial of recombinant ALP for infantile hypophosphatasia has already started in Japan. In future, such enzyme replacement therapy is expected to be adapted to fetus. There are several reports of mesenchymal stem cell transplantation for osteogenesis imperfecta fetus. These case reports have showed that stem cell transplantation is safe and to some extent works in patients. No clinical trial for gene therapy has been reported. Recently, the study of gene therapy of using HPP fetal mouse showed an excellent therapeutic effect. Fetal therapy of skeletal dysplasias is still the stage of research because of the safety and the ethical issues. However, in order to treat severe cases of skeletal dysplasias which abnormal development has been already completed at birth, fetal therapy at an early stage would be demanded.

Ultrasound prognostic factors after laser surgery for twin-twin transfusion syndrome to predict survival at 6 months.

OBJECTIVE: To evaluate the significance of ultrasound findings, detected one or two weeks after laser surgery for twin-twin transfusion syndrome, in predicting the mortality at 6 months of age. METHODS: Ultrasound evaluation including fetal biometry, amniotic fluid volume estimation and Doppler examination was performed between 7 and 14 days after surgery for 181 cases. The presence of one or more effusions and single fetal death were also determined. Associations between ultrasound findings and mortality at 6 months of age were evaluated using multiple logistic regression analysis. RESULTS: Of the total 181 pairs, 145 (80.1%) donor and 160 (88.1%) recipient twins survived in utero for more than 7 days after surgery, and hence were included in the analysis. The survival rate at 6 months was 66.9% for the donor and 80.7% for the recipient twins. Risk factors for death in the donor were the presence of severe intrauterine growth restriction and effusions. In recipients, elevation in the middle cerebral artery peak systolic velocity coincided with fetal death, but this occurred in only three cases. CONCLUSION: Ultrasound risk factors one week after surgery included severe intrauterine growth restrictions and effusions in the donor twins.

Antenatal three-dimensional sonographic features of Roberts syndrome.

INTRODUCTION: We present a fetus whose characteristics most likely represent Roberts syndrome. CASE REPORT: Prenatal diagnosis at 21 weeks and 1 day age of gestation was made employing conventional two-dimensional (2D) sonography, showing shortened upper and lower extremities. An umbilical cord cyst was also noted. Three-dimensional (3D) sonography revealed additional abnormalities which included bilateral hypoplastic and proximal implantation of the thumb, exophthalmic eyes, and suspected cleft lip. Shortened upper extremities, contracted legs, and an umbilical cord cyst were also clearly confirmed. Transparent X-ray mode uncovered the absence of radial and ulnar bones. Subtle fetal structures were readily discernible with 3D sonography so that the family could understand the fetal condition in utero. They underwent counseling, and opted for termination of the pregnancy. The sonographic findings were confirmed after delivery, supported by a 3D computed tomographic skeletal survey. CONCLUSION: To the best of our knowledge, this is the first report of Roberts syndrome employing antenatal 3D sonographic imaging.

The outcome and prognostic factors of twin-twin transfusion syndrome following fetoscopic laser surgery.

OBJECTIVES: To evaluate the outcome and preoperative risks of twin-twin transfusion syndrome (TTTS) following fetoscopic laser surgery (FLS). METHODS: A retrospective cohort study of a series of 181 consecutive cases of TTTS before 26 weeks' gestation subjected to FLS at four centers in Japan between July 2002 and December 2006. RESULTS: The chances of survival of at least one twin at 28 days of age and 6 months of age were 91.2% and 90.1%, respectively. The rate of major neurological complications in survivors at 6 months of age was 4.7%. Preoperative findings that were significant risk factors for death were as follows: (1) being donor [odds ratio (OR): 3.01, 95% confidence interval (CI): 1.24-7.31, P = 0.015]; (2) reversed (OR: 11.78, CI: 3.05-45.55, P < 0.001) and absent (OR: 3.95, CI: 1.66-9.43, P = 0.002) end-diastolic velocity in the umbilical artery (EDV-UA) of the donor; and (3) reversed blood flow in the ductus venosus of the recipient (OR: 2.35, CI: 1.04-5.29, P = 0.040). CONCLUSIONS: FLS leads to high survival rates and low neurological morbidity for fetuses in TTTS. FLS is an effective therapeutic option for TTTS before 26 weeks of gestation. Preoperative Doppler findings of the umbilical artery and the ductus venosus are useful in predicting prognosis following FLS.