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Biomedical subjects

Kenji Kurosawa

Publications and source records attributed to Kenji Kurosawa.

At least 19 recordsLinked to original sources

Origin and mechanisms of formation of fetus-in-fetu: two cases with genotype and methylation analyses.

Fetus-in-fetu (FIF) is a condition in which a host infant has a fetus-like mass(es) within its body. We describe here results of molecular genetic analysis in two cases of FIF. In FIF-1, a male host had two retroperitoneal fetiform masses each with a vertebral column, and in FIF-2, a fetiform mass with vertebral column was present in the cranial cavity of a male host. Genotyping of each case using microsatellite markers showed that the host infant and its fetus(es) inherited one copy each of parental alleles and shared identical genotypes. These findings were confirmed by single nucleotide polymorphism (SNP) analysis using Affymetrix GeneChip Human Mapping 50K Array, and supported a monozygotic twin theory of FIF. Analysis of the methylation status was done in both cases at the differentially methylated region (DMR) within the human IGF2-H19 locus after bisulfite treatment, methylation-specific PCR, and cloning of PCR products. Normally, only the paternal allele is methylated and the maternal allele unmethylated in DMR. However, in FIF-1, 7 (46.7%) of 15 clones from a fetiform mass and 6 (66.7%) of 9 clones from the other mass showed an unmethylated paternal allele, while the methylation status of a host infant and its fetiform mass in FIF-2 was the same in all clones examined with normal patterns. These data suggest that in FIF-1, two isolated blastocysts originated from one zygote, one of the two was implanted into (or included by) the other blastocyst during the process of methylation, and such abnormal implantation may have occurred in FIF-2 after the establishment of methylation. This is the first case of FIF showing different methylation patterns between a host infant and fetiform mass.

Adult↗

Trigonocephaly in a boy with paternally inherited deletion 22q11.2 syndrome.

Deletion 22q11.2 syndrome is a well-known contiguous gene syndrome, for which the list of findings is extensive and varies from patient to patient. We encountered a unique patient who had a familial 3-Mb deletion 22q11.2 associated with trigonocephaly derived from craniosynostosis of the metopic suture. Almost all the symptoms of the patient, including polymicrogyria, microcephaly, facial abnormalities, internal anomalies, seizures, and mental retardation, were compatible with deletion 22q11.2 syndrome, except for synostosis of the metopic suture. This is the first report of a relationship between deletion 22q11.2 syndrome and trigonocephaly. Craniosynostosis of the metopic suture might be a minor complication of deletion 22q11.2, although coincidental occurrence cannot be ruled out.

Abnormalities, Multiple↗

Pregnancy outcome of fetuses with trisomy 18 identified by prenatal sonography and chromosomal analysis in a perinatal center.

To investigate the pregnancy outcome of fetuses affected with trisomy 18, we analyzed 63 cases diagnosed at our hospital from January 1993 to December 2004. Twenty-nine were males and 34 were females. Fifty-eight were prenatally diagnosed, and in 16 (27.6%) of them intrauterine fetal death (IUFD) occurred between 28 weeks and 41 weeks gestation (34.6 +/- 3.9 weeks, Mean +/- SD). Ten (17.2%) fetuses died during labor and their age ranged from 30 weeks to 40 weeks of gestation. The total number of cases ending in fetal demise was 26 (44.8%) and the mean gestational age at the time of fetal demise was 35.0 +/- 3.6 weeks (Mean +/- SD). All liveborn infants (n = 36) were born after 31 weeks gestation. In our study the preterm birth ratio for trisomy 18 is 34.8%, which is much higher than the ratio for the general population. Females are more likely than males to be long-term survivors. These data are helpful in the counseling of parents faced with the difficult decision of whether or not to continue a pregnancy with a fetus affected with trisomy 18.

Chromosomes, Human, Pair 18↗

Germline KRAS and BRAF mutations in cardio-facio-cutaneous syndrome.

Cardio-facio-cutaneous (CFC) syndrome is characterized by a distinctive facial appearance, heart defects and mental retardation. It phenotypically overlaps with Noonan and Costello syndrome, which are caused by mutations in PTPN11 and HRAS, respectively. In 43 individuals with CFC, we identified two heterozygous KRAS mutations in three individuals and eight BRAF mutations in 16 individuals, suggesting that dysregulation of the RAS-RAF-ERK pathway is a common molecular basis for the three related disorders.

Amino Acid Sequence↗

BAC array CGH reveals genomic aberrations in idiopathic mental retardation.

Array using 2,173 BAC clones covering the whole human genome has been constructed. All clones spotted were confirmed to show a unique signal at the predicted chromosomal location by FISH analysis in our laboratory. A total of 30 individuals with idiopathic mental retardation (MR) were analyzed by comparative genomic hybridization using this array. Three deletions, one duplication, and one unbalanced translocation could be detected in five patients, which are likely to contribute to MR. The constructed array was shown to be an efficient tool for the detection of pathogenic genomic rearrangements in MR patients as well as copy number polymorphisms (CPNs).

Chromosome Aberrations↗

A large interstitial deletion of 17p13.1p11.2 involving the Smith-Magenis chromosome region in a girl with multiple congenital anomalies.

A 6-month-old girl had multiple congenital anomalies, including dysmorphic face; tetralogy of Fallot, pulmonary atresia and patent ductus arteriosus; congenital cystic adenomatoid malformation of the right upper lung, and hemilateral kidney defect. Chromosome analysis as well as fluorescence in situ hybridization (FISH) and polymorphic marker analyses in the girl and her parents revealed a de novo large interstitial deletion of 17p13.1-p11.2 of the paternally derived chromosome 17. The deletion involved the Smith-Magenis chromosome region (SMCR). Lack of involvement of the Miller-Dieker syndrome region at 17p13.3 was confirmed by both FISH analysis and radiological examinations that showed no migrational abnormality. The girl died at age 7 months. This is the first report of a patient with a large interstitial deletion of 17p.

Abnormalities, Multiple↗

Congenital neuroblastoma in a patient with partial trisomy of 2p.

We report the fourth example of a patient with germline partial trisomy of 2p21-pter and congenital neuroblastoma. The male infant had a dysmorphic facial expression and presented with congenital heart disease, supernumerary nipples, hypospadias, shawl scrotum, hemilateral persistent hyperplastic primary vitreous, and neuroblastoma. His germline karyotype of 46,XY,der(8)t(2;8)(p21;p23.2) was inherited from a maternal-balanced translocation, which indicates that the proto-oncogene MYCN region of 2p24.3 is tripicated in germline cells. A cytogenetic study of the biopsied tumor cells did not show MYCN amplification, but the DNA index was 2.4 and histologic fluorescent in situ hybridization analysis indicated somatic mutation with near-pentaploidy of the tumor cells. This could be an alternative mechanism of MYCN activation in the process of the tumorigenesis of neuroblastoma.

Abnormalities, Multiple↗

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.

Brain↗

Detection of cryptic chromosome aberrations in a patient with a balanced t(1;9)(p34.2;p24) by array-based comparative genomic hybridization.

Mental retardation (MR) is one of the most common phenotypes in congenital disorders, but in many cases the pathogenesis remains unknown. Here, we report on a 5-year-old boy with mild developmental disability, cranial malformation, minor anomalies, and moderate MR. G-banded chromosome analysis revealed that he carried an apparent balanced translocation, t(1;9)(p34.2;p24). However, our array-based comparative genomic hybridization (CGH-array) analysis detected a cryptic genomic duplication and a deletion at the breakpoints. Further fluorescence in situ hybridization (FISH) showed that the duplication was approximately 7.9 Mb in size at 1p34.3-p33, and the deletion was 4 Mb at 9pter-p24. Although some features of the patient were consistent with those of monosomy 9p-syndrome, his features were not typical of cases of the syndrome, suggesting that the small deletion region involved in 9p may limit his phenotype. On the other hand, interstitial duplication at 1p34.3-p33 is very rare and his phenotype did not match with that in previous reports. CGH-array is a potentially useful technique for investigating cryptic copy-number alterations in cases of apparently balanced chromosome rearrangements in patients with unexpected clinical features.

Abnormalities, Multiple↗

Genomic rearrangement at 10q24 in non-syndromic split-hand/split-foot malformation.

Split-hand/split-foot malformation (SHFM) is a congenital limb malformation characterized by a median cleft of hand and/or foot due to the absence of central rays. Five loci for syndromic and non-syndromic SHFM, termed SHFM1-5, have been mapped to date. Recently, a 0.5 Mb tandem genomic duplication was found at chromosome 10q24 in SHFM3 families. To refine the minimum duplicated region and to further characterize the SHFM3 locus, we screened 28 non-syndromic SHFM families for tandem genomic duplication of 10q24 by Southern blot and sequence analysis of the dactylin gene. Of 28 families, only two showed genomic rearrangements. Representative patients from the two families exhibit typical SHFM, with symmetrically affected hands and feet. One patient is a familial case with a 511,661 bp tandem duplication, whereas the second is a sporadic case arising from a de novo, 447,338 bp duplication of maternal origin. The smaller duplication in the second patient contained the LBX1, BTRC, POLL, and DPCD genes and a disrupted extra copy of the dactylin gene, and was nearly identical to the smallest known duplicated region of SHFM3. Our results indicate that genomic rearrangement of SHFM3 is rare among non-syndromic SHFM patients and emphasize the importance of screening for genomic rearrangements even in sporadic cases of SHFM.

Chromosomes, Human, Pair 10↗

Segmental and full paternal isodisomy for chromosome 14 in three patients: narrowing the critical region and implication for the clinical features.

We report on segmental and full paternal isodisomy for chromosome 14 in three previously unreported Japanese patients. Patient 1 was a 5(6/12)-year-old girl, Patient 2 was a male neonate, and Patient 3 was a -year-old girl. Physical examination at birth showed various somatic features characteristic of paternal uniparental disomy for chromosome 14 (upd(14)pat) such as hairy forehead, protruding philtrum, micrognathia, small thorax, and abdominal wall defects in Patients 1-3, and the constellation of somatic features was persistently observed in Patients 1 and 3. Radiological studies at birth delineated unique bell-shaped thorax with coat-hanger appearance of the ribs in Patients 1-3, but the thoracic deformity ameliorated in Patients 1 and 3 by mid childhood. Chromosome analysis showed a 46,XX karyotype in Patients 1 and 3 and was not performed in Patient 2. Microsatellite analysis indicated full paternal isodisomy for chromosome 14 in Patients 1 and 2 and segmental paternal isodisomy for chromosome 14 distal to D14S981 at 14q23.3 in Patient 3. Methylation specific PCR assay for the differentially methylated region (DMR) of GTL2 at 14q32 yielded positive products with methylated allele specific primers and no products with unmethylated allele specific primers in Patients 1-3. Since clinical phenotype was similar between Patient 3 with segmental upd(14)pat and Patients 1 and 2 with full upd(14)pat, the results are keeping with the 14q32 localized imprinted genes as the critical components of the phenotype observed in upd(14)pat and help narrow the search for additional genes to the approximately 40 Mb region distal to D14S981. Furthermore, it is likely that the characteristic thoracic deformity ameliorates with age.

Child↗

Germline mutations in HRAS proto-oncogene cause Costello syndrome.

Costello syndrome is a multiple congenital anomaly and mental retardation syndrome characterized by coarse face, loose skin, cardiomyopathy and predisposition to tumors. We identified four heterozygous de novo mutations of HRAS in 12 of 13 affected individuals, all of which were previously reported as somatic and oncogenic mutations in various tumors. Our observations suggest that germline mutations in HRAS perturb human development and increase susceptibility to tumors.

Abnormalities, Multiple↗

Brain MRI findings of older patients with Pallister-Killian syndrome.

Pallister-Killian syndrome (PKS) is a disorder caused by a mosaic tetrasomy of chromosome 12p, which manifests with dysmorphism, intellectual disabilities, auditory disturbance, and epilepsy. Here, we describe the findings of brain magnetic resonance (MR) imaging in two patients with PKS. One patient, a 43-year-old man, showed multiple lesions with high signal intensity on T2-weighted image (WI) in the basal ganglia, and widespread T2 elongation in the periventricular white matter. The same signal change was also present in the pontine base. The other patient, a 37-year-old woman, showed T2-high lesions in the bilateral putamina and the parietal periventricular white matter. There was prominent atrophy of the cerebellum and brainstem in this latter case. Both cases showed cortical atrophy with frontal predominance, with accompanying dilatation of the lateral ventricles. Hypoplastic corpus callosum was also present in both cases. Cerebral atrophy with ventricular dilatation has been often described in PKS cases, but many of the MR findings in the present patients have never been reported. Such findings may appear with advancing age in PKS. Since 12p mosaicism is rarely detected in peripheral blood lymphocytes, examination of buccal mucosal cells with fluorescent in situ hybridization method is preferable for the diagnosis of PKS. Recognition of the characteristic features on cranial MR imaging, in addition to the characteristic facial appearance in adulthood, should prompt the correct diagnosis of adult PKS patients.

Adult↗

Congenital anomaly of cervical vertebrae is a major complication of Rubinstein-Taybi syndrome.

Rubinstein-Taybi syndrome (RTS; MIM# 180849) is a well-known malformation syndrome, characterized by broad thumbs and halluces, a characteristic facies, short stature, and mental retardation. RTS is accompanied by a variety of morbid complications, particularly of the skeleton. Based on the experience of five RTS patients with malformation of the craniovertebral junction, we draw attention to previously unrecognized life-threatening complications of RTS, including instability of C1-C2, os odontoideum, hypoplasia of the dens, and fusion of the cervical vertebrae. One patient developed severe cervical myelopathy. Malformation of the cervical spine may be a common syndromic constituent of RTS, to which special attention should be paid to prevent its neurologic sequelae.

Adolescent↗

Functional analysis of PTPN11/SHP-2 mutants identified in Noonan syndrome and childhood leukemia.

Noonan syndrome (NS) is characterized by short stature, characteristic facial features, and heart defects. Recently, missense mutations of PTPN11, the gene encoding protein tyrosine phosphatase (PTP) SHP-2, were identified in patients with NS. Further, somatic mutations in PTPN11 were detected in childhood leukemia. Recent studies showed that the phosphatase activities of five mutations identified in NS and juvenile myelomonocytic leukemia (JMML) were increased. However, the functional properties of the other mutations remain unidentified. In this study, in order to clarify the differences between the mutations identified in NS and leukemia, we examined the phosphatase activity of 14 mutants of SHP-2. We identified nine mutations, including a novel F71I mutation, in 16 of 41 NS patients and two mutations, including a novel G503V mutation, in three of 29 patients with leukemia. Immune complex phosphatase assays of individual mutants transfected in COS7 cells showed that ten mutants identified in NS and four mutants in leukemia showed 1.4-fold to 12.7-fold increased activation compared with wild-type SHP-2. These results suggest that the pathogenesis of NS and leukemia is associated with enhanced phosphatase activity of mutant SHP-2. A comparison of the phosphatase activity in each mutant and a review of previously reported cases showed that high phosphatase activity observed in mutations at codons 61, 71, 72, and 76 was significantly associated with leukemogenesis.

Adolescent↗