Compound heterozygous variants in RAB34 in a rare skeletal ciliopathy syndrome.

Skeletal ciliopathies are a heterogenous group of congenital disorders characterized by multiple internal abnormalities, and distinct radiographic presentation. Pathogenic variants in at least 30 cilia genes are known to cause skeletal ciliopathies. Here we report a fetus with an atypical skeletal ciliopathy phenotype and compound heterozygous variants in the RAB34 gene. The affected fetus had multiple malformations, including posterior neck edema, micrognathia, low-set and small ears, auricular hypoplasia, cleft lip and palate, short extremities, and a combination of rarely occurring pre- and postaxial polydactyly. Genome sequencing identified compound heterozygous variants in the RAB34 gene: maternal c.254T>C, p.(Ile85Thr), and paternal c.691C>T, p.(Arg231*) variants. Only the paternal variant was present in the unaffected sibling. Evidence in the literature indicated that Rab34-/- mice displayed a ciliopathy phenotype with cleft palate and polydactyly. These features were consistent with malformations detected in our patient supporting the pathogenicity of the identified RAB34 variants. Overall, this case report further expands genetic landscape of human ciliopathy syndromes and suggests RAB34 as a candidate gene for skeletal ciliopathies.

Aortic Dissection and a Previously Unreported ACTA2 Missense Variant Mutation in a Young Patient: A Case Report.

Hereditary connective tissue disease is known to cause aortic lesions at an early age. Familial aortic aneurysm/dissection is caused due to an ACTA2 mutation that affects smooth muscle structure. We present a case of a 15-year-old boy with a mild developmental disorder in whom no abnormalities were identified on previous physical examinations. The patient presented with severe left heart failure, extensive dissection from the ascending aorta to the common iliac artery, and myocardial and cerebral infarctions. He underwent an urgent Bentall surgery. Six months later, the patient underwent surgical reconstruction of the abdominal aorta from the aortic arch and returned to normal daily activities. Pathological examination demonstrated the absence of elastic fibers but presence of abundant reticular fibers and mucopolysaccharides from the tunica intima to the media. Genetic testing revealed a heterozygous missense variant of the ACTA2 gene. To the best of our knowledge, this is the first sporadic case of structurally abnormal smooth muscle organization resulting in clinical symptoms with no previously reported pathogenicity.

Somatic mosaicism of the PI3K-AKT-MTOR pathway is associated with hemimegalencephaly in fetal brains.

It is known that somatic activation of PI3K-AKT-MTOR signaling causes malformations of cortical development varying from hemimegalencephaly to focal cortical dysplasia. However, there have been few reports of fetal cases. Here we report two fetal cases of hemimegalencephaly, one associated with mosaic mutations in PIK3CA and another in AKT1. Both brains showed polymicrogyria, multiple subarachnoidal, subcortical, and subventricular heterotopia resulting from abnormal proliferation of neural stem/progenitor cells, cell differentiation, and migration of neuroblasts. Scattered cell nests immunoreactive for phosphorylated-S6 ribosomal protein (P-RPS6) (Ser240/244) were observed in the polymicrogyria-like cortical plate, intermediate zone, and arachnoid space, suggesting that the PI3K-AKT-MTOR pathway was actually activated in these cells. Pathological analyses could shed light on the mechanisms involved in disrupted brain development in the somatic mosaicism of the PI3K-AKT-MTOR pathway.

Detailed analysis of 26 cases of 1q partial duplication/triplication syndrome.

Partial 1q trisomy syndrome is a rare disorder. Because unbalanced chromosomal translocations often occur with 1q trisomy, it is difficult to determine whether patient symptoms are related to 1q trisomy or other chromosomal abnormalities. The present study evaluated genotype-phenotype correlations of 26 cases diagnosed with 1q partial trisomy syndrome. DNA microarray was used to investigate the duplication/triplication region of 16 cases. Although there was no overlapping region common to all 26 cases, the 1q41-qter region was frequently involved. One case diagnosed as a pure interstitial trisomy of chromosome 1q by G-banded karyotype analysis was instead found to be a pure partial tetrasomy by CytoScan HD Array. In four 1q trisomy syndrome cases involving translocation, the translocated partner chromosome could not be detected by DNA microarray analyzes despite G-banded karyotype analysis, because there were a limited number of probes available for the partner region. DNA microarray and G-banded karyotyping techniques were therefore shown to be compensatory diagnostic tools that should be used by clinicians who suspect chromosomal abnormalities. It is important to continue recruiting affected patients and observe and monitor their symptoms to reveal genotype-phenotype correlations and to fully understand their prognosis and identify causal regions of symptoms.

Congenital diaphragmatic hernia interval on chromosome 8p23.1 characterized by genetics and protein interaction networks.

Chromosome 8p23.1 is a common hotspot associated with major congenital malformations, including congenital diaphragmatic hernia (CDH) and cardiac defects. We present findings from high-resolution arrays in patients who carry a loss (n = 18) or a gain (n = 1) of sub-band 8p23.1. We confirm a region involved in both diaphragmatic and heart malformations. Results from a novel CNVConnect algorithm, prioritizing protein-protein interactions between products of genes in the 8p23.1 hotspot and products of previously known CDH causing genes, implicated GATA4, NEIL2, and SOX7 in diaphragmatic defects. Sequence analysis of these genes in 226 chromosomally normal CDH patients, as well as in a small number of deletion 8p23.1 patients, showed rare unreported variants in the coding region; these may be contributing to the diaphragmatic phenotype. We also demonstrated that two of these three genes were expressed in the E11.5-12.5 primordial mouse diaphragm, the developmental stage at which CDH is thought to occur. This combination of bioinformatics and expression studies can be applied to other chromosomal hotspots, as well as private microdeletions or microduplications, to identify causative genes and their interaction networks.

NSAIDs and acidic environment induce gastric mucosal cellular mitochondrial dysfunction.

Non-steroidal anti-inflammatory drugs (NSAIDs) often cause gastrointestinal complications such as gastric ulcers and erosions. Recent studies on the pathogenesis have revealed that NSAIDs induce lipid peroxidation in gastric epithelial cells by generating superoxide in mitochondria, independently with cyclooxygenase inhibition and the subsequent prostaglandin deficiency. More recently, gastric hydrochloric acid (HCl) has been regarded as an inciting factor of gastric mucosal injuries, and reportedly induced cellular lipid peroxidation in vitro. We hypothesized that gastric acid and NSAID treatment synergistically induce cellular injury in gastric epithelial cells. We treated gastric epithelial RGM1 cells with acidic solutions and NSAIDs, and examined cellular injury, lipid peroxidation, mitochondrial transmenbrane potential and mitochondrial superoxide. We pretreated RGM1 cells with the acidic solutions for 0.5 h and after that treated them with each NSAID for 15 h and found that the exposure to acid and NSAIDs indeed induced cellular injury. We hypothesized that gastric acid and NSAID treatment synergistically induce mitochondrial superoxide production, which induces gastric cellular injury.

Axenfeld-Rieger anomaly and Axenfeld-Rieger syndrome: clinical, molecular-cytogenetic, and DNA array analyses of three patients with chromosomal defects at 6p25.

Clinical phenotypes of and genetic aberrations in three unrelated Japanese patients with Axenfeld-Rieger anomalies and various accompanying malformations of systemic organs are described. GTG-banded chromosome analysis showed terminal deletions of the short arm of chromosome 6 in two patients and an inversion, inv(6)(p25q14), in the other. FISH and DNA array analyses revealed that the two patients with deletions had 5.0-5.7 Mb and 6.6 Mb 6p terminal deletions, respectively, and FOXC1 was apparently deleted in both patients. In the other patient, the inversion breakpoint at 6p25 was estimated to be in or very close to the FOXC1 locus, but DNA array analysis did not reveal a deletion around the breakpoint. Common extraocular findings in these patients included broad forehead, brachycephaly, hypertelorism, downslanting palpebral fissures, small anteverted nose, and cardiac defects. Two patients also exhibited autistic characteristics. The two patients with deletions exhibited poor muscle tone and developmental delays. Most of these extraocular findings were similar to those found in previous patients with FOXC1 mutations and distinct from those found in patients with PITX2 mutations, who frequently develop umbilical and dental anomalies. We suggest that the psychomotor retardation is a clinical manifestation associated with a deletion of multiple contiguous genes in the 6p terminus and that this phenomenon is similar to the 6p25 deletion syndrome. Understanding the relationship between genetic lesions and the spectrum of extraocular findings in patients with Axenfeld-Rieger anomalies may lead to better clinical management.

De novo 5q14.3 translocation 121.5-kb upstream of MEF2C in a patient with severe intellectual disability and early-onset epileptic encephalopathy.

Recent studies have shown that haploinsufficiency of MEF2C causes severe intellectual disability, epilepsy, hypotonia, and cerebral malformations. We report on a female patient with severe intellectual disability, early-onset epileptic encephalopathy, and hypoplastic corpus callosum, possessing a de novo balanced translocation, t(5;15)(q13.3;q26.1). The patient showed upward gazing and tonic seizure of lower extremities followed by generalized clonic seizures at 4 months of age. Electroencephalogram showed hypsarrhythmia when asleep. By using fluorescent in situ hybridization (FISH), southern hybridization and inverse PCR, the translocation breakpoints were determined at the nucleotide level. The 5q14.3 breakpoint was localized 121.5-kb upstream of MEF2C. The 15q26.2 breakpoint was mapped 119-kb downstream of LOC91948 non-coding RNA. We speculate that the translocation may disrupt the proper regulation of MEF2C expression in the developing brain, resulting in severe intellectual disability and early-onset epileptic encephalopathy.

D-karyo-A New Prenatal Rapid Screening Test Detecting Submicroscopic CNVs and Mosaicism.

Chromosomal microarray analysis (CMA), recently introduced following conventional cytogenetic technology, can detect submicroscopic copy-number variations (CNVs) in cases previously diagnosed as "cytogenetically benign". At present, rapid and accurate chromosomal analysis is required in prenatal diagnostics, but prenatal CMA is not widely used due to its high price and long turnaround time. We introduced a new prenatal screening method named digital karyotyping (D-karyo), which utilizes a preimplantation genetic test for the aneuploidy (PGT-A) platform. First, we conducted a preliminary experiment to compare the original PGT-A method to our modified method. Based on the preliminary results, we decided to implement the modified strategy without whole-genome amplification (WGA) and combined it with three analytical software packages. Next, we conducted a prospective study with 824 samples. According to the indication for invasive tests, the D-karyo positive rates were 2.5% and 5.0%, respectively, in the screening positive group with NT ≥ 3.5 mm and the group with fetal abnormalities by ultrasound. D-karyo is a breakthrough modality that can detect submicroscopic CNVs ≥ 1.0 Mb accurately in only 10.5 h for 24 samples at a low cost. Implementing D-karyo as a prenatal rapid screening test will reduce unnecessary CMA and achieve more accurate prenatal genetic testing than G-banding.

Clinical Validation of Fetal cfDNA Analysis Using Rolling-Circle-Replication and Imaging Technology in Osaka (CRITO Study).

BACKGROUND: Noninvasive prenatal genetic testing (NIPT) has been adopted as the first choice for aneuploidy screening. The purposes of this study were to investigate the accuracy of Vanadis® NIPT (hereafter CRITO-NIPT) in order to gain a deeper insight into the reasons for discrepancies, as well as to discuss the role of fetal ultrasound. METHODS: Between 2019 and 2020, CRITO-NIPT was performed in 1218 cases of patients who underwent CVS or amniocentesis after a detailed fetal ultrasound exam and genetic counseling. The CRITO-NIPT results were compared with the genetic results. In cases of test discrepancies, the placentae were collected for detailed genetic research, and the pre-procedure fetal ultrasound findings were referred to. RESULTS: The positive predictive value of T21, T18, and T13 was 93.55%, 88.46%, and 100%, respectively. In 90% of the of false positive (FP) cases, the placentae were examined. In 75% of the CRITO FP-T21 cases, placental mosaicism, or a demised twin's T21, were confirmed. There were complicated mosaic cases, including tetrasomy 21/trisomy7 and monosomy 21/trisomy21 cases. In one of three no-call cases, an intermediate deletion of chromosome 13 was detected. CONCLUSIONS: The CRITO study investigated the mechanism of false positives, and the detailed mechanisms in mosaic and no-call cases. There have hitherto been no reports that have provided insight by partitioning the placenta to compare the NIPT and invasive test results, nor that have provided detailed ultrasound findings in the cases of discordant results, revealing the demonstrated importance of, and necessity for, detailed ultrasonography. This article describes the potential of rolling-circle replication as a powerful biosensing platform, as well as the importance of examining the fetus in detail with ultrasound. However, we should remember that the potential applications raise ethical and social concerns that go beyond aneuploidy and its methodology.

Fetal Megalencephaly with Cortical Dysplasia at 18 Gestational Weeks Related to Paternal UPD Mosaicism with PTEN Mutation.

The phosphatase and tensin homolog (PTEN) gene is a tumor-suppressor gene located on 10q22-23. Since the introduction of molecular genetics in prenatal diagnostics, various birth defects associated with gene mutations have been diagnosed. However, no reports on fetal cases related to PTEN mutation have been found, so far. We encountered a rare case of fetal PTEN mutation. Fetal macrocephaly was noted at 16 weeks. At 18 and 20 weeks, neurosonography revealed megalencephaly with an asymmetrical structure and multifocal polygyria. The head circumference (HC) was +6.2 SD at 18 weeks and +8.1 SD at 20 weeks. The parents opted for pregnancy termination, and the male fetus was delivered at 21 weeks, with HC +9.3 SD. Single-nucleotide polymorphism (SNP) array for amniotic cells showed paternal uniparental disomy (UPD) 10q mosaicism, and the mosaic ratio was calculated as 56% from B-allele frequency. Exome sequencing revealed the pathogenic PTEN mutation with mosaicism. The heterozygous PTEN mutation may not cause early manifestations from the fetal period, and an abnormal phenotype may appear after birth. This may be the reason why fetal defects associated with PTEN mutation are not detected. Since this case had homozygous and heterozygous mutations, survival was possible, exhibiting an incredibly huge head with cortical dysplasia from early pregnancy.

Prenatal findings in a fetus with contiguous gene syndrome caused by deletion of Xp22.3 that includes locus for X-linked recessive type of chondrodysplasia punctata (CDPX1).

The X-linked recessive type of chondrodysplasia punctata (CDPX1) is a skeletal disorder that is characterized by stippled calcification at an epiphyseal nucleus and the surrounding soft tissue, short stature and an unusual face because of nasal hypoplasia. In most of the patients, this condition is noted after birth because of a characteristic face or respiratory problems. Here, we report a fetus with CDPX1. Two-dimensional ultrasound examination revealed unexplained polyhydramnios and a male fetus. Fetal biometry showed shortened long bones. Three-dimensional ultrasonography clearly demonstrated a hypoplastic nose with a depressed nasal bridge and contracture of wrists and fingers. Chromosome analysis of the amniotic fluid cells revealed the 46,Y,del(X)(p22.3) karyotype. Fluorescence in situ hybridization revealed a deletion of subtelomeric sequences at the Xpter and STS gene, but not a deletion of the KAL gene. The genomic copy number analysis demonstrated terminal deletion of 8.33 Mb that included SHOX, CSF2RA, XG, ARSE, NLGN4 and STS genes. We think that our case presents typical features of a fetus with this disorder and will be of great help in prenatal ultrasound diagnosis.

Neoplastic transformation and induction of H+,K+ -adenosine triphosphatase by N-methyl-N'-nitro-N-nitrosoguanidine in the gastric epithelial RGM-1 cell line.

N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induces gastric cancer in animal models. We established an MNNG-induced mutant of the rat murine RGM-1 gastric epithelial cell line, which we named RGK-1, that could be used as an in vitro model of gastric cancer. This cell line showed signs of neoplasia and transformation, in that it lost contact inhibition and formed tumors in nude mice. The mutant cells also expressed parietal cell-specific H(+),K(+)-adenosine triphosphatase (H(+),K(+)-ATPase), which parent RGM-1 did not. The results suggested that parent RGM-1 cells were gastric progenitor cells. This mutant RGK-1 cell line will contribute to future investigation on gastric carcinogenesis and to the development of other pathophysiologic fields.

Cellular membrane fluidity measurement by fluorescence polarization in indomethacin-induced gastric cellular injury in vitro.

BACKGROUND: Gastric complications of indomethacin involve generation of reactive oxygen species, which induce gastric mucosal injury via lipid peroxidation of cell membranes. Peroxidation by reactive oxygen species alters the amounts of unsaturated fatty acids in the cell membrane and thus affects membrane fluidity. Indomethacin-induced lipid peroxidation can thus be detected by measuring cellular membrane fluidity by the fluorescence polarization (FP) method. The aim of this study was to elucidate the usefulness of the FP method for detecting indomethacin-induced gastric cellular injury in RGM-1 cells. METHODS: Indomethacin-treated RGM-1 cells were investigated by conventional cytotoxicity assay, fluorometry of diphenyl-1-pyrenylphosphine (DPPP) to detect lipid peroxidation, and FP. The effects of both a radical scavenger and an initiator on membrane fluidity change (MFC) in RGM-1 cells were examined. The sensitivity of FP in detecting cellular injury was compared with those of DPPP fluorometry and conventional cytotoxicity measurements. RESULTS: Indomethacin caused an increase in MFC as determined by FP before cytotoxicity was detected by conventional methods. The increase in MFC was associated with increased membrane phospholipid peroxidation (MPP) but not with a prostaglandin deficiency, and the increases in both MFC and MPP were prevented by vitamin E. CONCLUSIONS: The FP method is potentially useful for detecting cellular injury in vitro.

Neuroradiologic findings in Sotos syndrome.

Sotos syndrome is a well-known anomaly syndrome characterized by overgrowth, characteristic facial gestalt, and developmental delay, and haploinsufficiency of the NSD1 gene has been revealed as one of the major genetic causes. However, there have been only a few reports on neuroradiologic findings by computed tomography (CT) or magnetic resonance imaging (MRI), and functional examination of the brain has not been reported. We examined three cases with typical Sotos syndrome, which also were confirmed by genetic analysis with a specific probe for the NSD1 gene. The results of MRI showed the characteristic features that have been reported previously. The findings obtained by using single-photon emission computed tomography and magnetic resonance spectroscopy suggested an association between mental delay and behavioral tendency in Sotos syndrome and immaturity in frontal brain function.

Mechanisms involved in delta-aminolevulinic acid (ALA)-induced photosensitivity of tumor cells: relation of ferrochelatase and uptake of ALA to the accumulation of protoporphyrin.

Photodynamic therapy (PDT) using delta-aminolevulinic acid (ALA)-induced accumulation of protoporphyrin IX is a useful approach to the early detection and treatment of cancers. To investigate the role of ferrochelatase in the accumulation of protoporphyrin, we first made mouse fibroblast Balb/3T3 cells highly expressing ferrochelatase and examined the ALA-induced photo-damage as well as the accumulation of porphyrin in the cells. When the ferrochelatase-transfected cells were treated with ALA and then exposed to visible light, they became resistant to the light without accumulating porphyrins, with a concomitant increase in the formation of heme. The accumulation of protoporphyrin was also abolished in human erythroleukemia K562 cells stably expressing mouse ferrochelatase. When mouse fibrosarcoma MethA cells, mouse fibroblast L929 cells and Balb/3T3 cells were treated with ALA, the greatest accumulation of protoporphyrin and the greatest level of cell death in response to the light were observed in MethA cells. The expression level of ferrochelatase was the lowest in MethA cells, while that of porphobilinogen deaminase was similar among all three cell lines. Moreover, an iron-chelator, desferrioxamine, which sequesters iron preventing the ferrochelatase reaction, enhanced the photo-damage as well as the accumulation of protoporphyrin in ALA-treated L929 cells. Thus, the light-induced cell death was tightly coupled with the accumulation of protoporphyrin caused by a decrease in ferrochelatase. Finally, we examined the uptake of ALA by MethA, L929 and Balb/3T3 cells. The extent of the uptake by MethA and L929 cells was greater, indicating a greater accumulation of protoporphyrin than in the Balb/3T3 cells. Taken together, not only the low level of ferrochelatase but also the augmented uptake of ALA contributes to the ALA-induced accumulation of protoporphyrin IX and subsequent photo-damage in cancer cells.

Fifty microdeletions among 112 cases of Sotos syndrome: low copy repeats possibly mediate the common deletion.

Sotos syndrome (SoS) is an autosomal dominant overgrowth syndrome with characteristic craniofacial dysmorphic features and various degrees of mental retardation. We previously showed that haploinsufficiency of the NSD1 gene is the major cause of SoS, and submicroscopic deletions at 5q35, including NSD1, were found in about a half (20/42) of our patients examined. Since the first report, an additional 70 SoS cases consisting of 53 Japanese and 17 non-Japanese have been analyzed. We found 50 microdeletions (45%) and 16 point mutations (14%) among all the 112 cases. A large difference in the frequency of microdeletions between Japanese and non-Japanese patients was noted: 49 (52%) of the 95 Japanese patients and only one (6%) of the 17 non-Japanese had microdeletions. A sequence-based physical map was constructed to characterize the microdeletions. Most of the microdeletions were confirmed to be identical by FISH analysis. We identified highly homologous sequences, i.e., possible low copy repeats (LCRs), in regions flanking proximal and distal breakpoints of the common deletion, This suggests that LCRs may mediate the deletion. Such LCRs seem to be present in different populations. Thus the different frequency of microdeletions between Japanese and non-Japanese cases in our study may have been caused by patient-selection bias.

Postnatal overgrowth by 15q-trisomy and intrauterine growth retardation by 15q-monosomy due to familial translocation t(13;15): dosage effect of IGF1R?

We report a 4-year-old boy, a 6-month-old girl, and a 17-week-old fetus all with a chromosomal imbalance derived from a balanced translocation t(13;15)(q34;q26.1) of their father. The boy had a partial trisomy for 15q26.1-qter (46,XY,der(13)t(13;15)(q34;q26.1)) and postnatal overgrowth, as well as craniosynostosis, facial anomalies, and finger joint contractures, while the girl with the same chromosomal aberration did not show overgrowth, although she had similar craniofacial and skeletal abnormalities. The fetus had a partial monosomy for 15q26.1-qter and intrauterine growth retardation (IUGR). Fluorescence in situ hybridization (FISH) analysis with a BAC clone covering the insulin-like growth factor 1 receptor gene (IGF1R) that is located to 15q25-q26 revealed three copies in the boy, one copy in the fetus, and two copies in their phenotypically normal father. Since deletion of IGF1Rhas repeatedly been reported to be associated with IUGR, it is tempting to speculate that the dosage of IGF1R may have determined growth in these children.