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Biomedical subjects

Takeshi Mizuguchi

Publications and source records attributed to Takeshi Mizuguchi.

15 recordsLinked to original sources

Osteogenesis imperfecta, intellectual disability and recurrent infections in a male with a pathogenic SASH3 variant.

Src Homology 3 Domain-containing Adaptor Protein 3 (SASH3) deficiency is an X-linked immune disorder. Here we identified a male case with a pathogenic SASH3 variant (c.1039C>T [p.Arg347Cys]) who presented with osteogenesis imperfecta, intellectual disability and recurrent infections. While immunological features in this case were characterized, further studies are needed to determine the association between the SASH3 variant and the skeletal or neurological manifestations.

Journal Article↗

Recent progress in genetics of Marfan syndrome and Marfan-associated disorders.

Marfan syndrome (MFS, OMIM #154700) is a hereditary connective tissue disorder, clinically presenting with cardinal features of skeletal, ocular, and cardiovascular systems. In classical MFS, changes in connective tissue integrity can be explained by defects in fibrillin-1, a major component of extracellular microfibrils. However, some of the clinical manifestations of MFS cannot be explained by mechanical properties alone. Recent studies manipulating mouse Fbn1 have provided new insights into the molecular pathogenesis of MFS. Dysregulation of transforming growth factor beta (TGFbeta) signaling in lung, mitral valve and aortic tissues has been implicated in mouse models of MFS. TGFBR2 and TGFBR1 mutations were identified in a subset of patients with MFS (MFS2, OMIM #154705) and other MFS-related disorders, including Loeys-Dietz syndrome (LDS, #OMIM 609192) and familial thoracic aortic aneurysms and dissections (TAAD2, #OMIM 608987). These data indicate that genetic heterogeneity exists in MFS and its related conditions and that regulation of TGFbeta signaling plays a significant role in these disorders.

Abnormalities, Multiple↗

Array comparative genomic hybridization analysis in first-trimester spontaneous abortions with 'normal' karyotypes.

Array comparative genomic hybridization (array CGH) analysis was conducted in chorionic villous samples from 20 first-trimester spontaneous abortions with G-banding normal chromosomes. A microarray, containing 2,173 BAC clones and covering the whole genome with a 1.5-Mb resolution, was constructed and used in the analysis. Two deletions were identified: a 1.4-Mb deletion at 3p26.2-p26.3 and a 13.7-Mb deletion at 13q32.3-qter. Reexamination of chromosome preparations from the sample with the 13.7-Mb deletion documented a mixture of cells with the 13q- chromosome and those with 46,XX chromosomes, the latter of which are likely to have been derived from contaminating decidual cells. This left the 1.4-Mb 3p deletion as the only instance with submicroscopic imbalance detected, giving a frequency of 1 in 19 (5%) G-banding normal abortions.

Abortion, Spontaneous↗

Comprehensive genetic analysis of relevant four genes in 49 patients with Marfan syndrome or Marfan-related phenotypes.

In order to evaluate the contribution of FBN1, FBN2, TGFBR1, and TGFBR2 mutations to the Marfan syndrome (MFS) phenotype, the four genes were analyzed by direct sequencing in 49 patients with MFS or suspected MFS as a cohort study. A total of 27 FBN1 mutations (22 novel) in 27 patients (55%, 27/49), 1 novel TGFBR1 mutation in 1 (2%, 1/49), and 2 recurrent TGFBR2 mutations in 2 (4%, 2/49) were identified. No FBN2 mutation was found. Three patients with either TGFBR1 or TGFBR2 abnormality did not fulfill the Ghent criteria, but expressed some overlapping features of MFS and Loeys-Dietz syndrome (LDS). In the remaining 19 patients, either of the genes did not show any abnormalities. This study indicated that FBN1 mutations were predominant in MFS but TGFBRs defects may account for approximately 5-10% of patients with the syndrome.

Activin Receptors, Type I↗

Mild craniosynostosis with 1p36.3 trisomy and 1p36.3 deletion syndrome caused by familial translocation t(Y;1).

We report on a 20-year-old man and a 16-year-old woman with a chromosomal imbalance derived from a balanced translocation, t(Y;1)(q12;p36.3) of the father. The man had a partial trisomy for 1p36.3-pter [46,X,der(Y)t(Y:1)(q12;p36.3)] and mild craniosynostosis of metopic and sagittal sutures as well as a borderline mental impairment, while the woman with a deletion for 1p36.3-pter [46,XX,der(1)t(Y;1)(q12;p36.3)] showed dysmorphic face with large anterior fontanel and severe developmental delay. Fluorescence in situ hybridization (FISH) showed that his trisomy spanned the 5.3-Mb region from 1p telomere harboring the critical region for craniosynostosis. To our knowledge, the man is the first case of a pure type of simple 1p36.3 trisomy as the effect of heterochromatic Yq12-qter deletion likely does not affect phenotype.

Adult↗

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.

5' Untranslated Regions↗

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.

Adult↗

Narrowing candidate region for monosomy 9p syndrome to a 4.7-Mb segment at 9p22.2-p23.

A 2-year-old boy with clinical manifestations of monosomy 9p syndrome and brown hair is described. G-banding and chromosome FISH studies demonstrated complex rearrangements involving seven breakpoints in chromosomes 2 and 9, which included a 6.6-Mb deletion at 9p22.2-p23. This, together with previous studies in the literature, narrowed the shortest region of overlap (SRO) for the syndrome to a 4.7-Mb interval. Candidate genes for trigonocephaly, mental retardation, and brown hair are discussed.

Abnormalities, Multiple↗

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↗

Molecular characterization of del(8)(p23.1p23.1) in a case of congenital diaphragmatic hernia.

A 36-week-old fetus was referred to the medical center because of his cystic mass and fluid in left thoracic cavity, and was delivered by cesarean section to manage neonatal problems at 37 weeks of gestation. Emergent surgical repair of the left diaphragmatic hernia was performed, but severe hypoxia persisted, and he expired on the following day. Chromosome analysis of cultured amniotic fluid cells indicated 46,XY,del(8)(p23.1p23.1). This is the fourth case of 8p23.1 deletion associated with diaphragmatic hernia. Microarray comparative genomic hybridization analysis using DNA of cultured amniotic fluid cells showed that six clones were deleted, which were mapped to the region between two low copy repeats (LCRs) at 8p23.1 previously described. Microsatellite analysis revealed that the deletion was of paternal origin, and his parents did not carry 8p23.1 polymorphic inversion. These data strongly suggested that the 8p23.1 interstitial deletion should have arisen through a different mechanism from that of inv dup del(8p) whose structural abnormality is always of maternal origin and accompanies heterozygous 8p23.1 polymorphic inversion in mother.

Adult↗

Molecular genetics of Marfan syndrome.

PURPOSE OF REVIEW: Marfan syndrome, the founding member of connective tissue disorders, is characterized by involvement of three major systems (skeletal, ocular, and cardiovascular) due to alteration in microfibrils. FBN1 at 15q21.1 was found to cause Marfan syndrome in 1991, and in 2004 TGFBR2 at 3p24.1 was newly identified as the Marfan syndrome type II gene. Several studies implied that fibrillin-1 and transforming growth factor-beta (TGF-beta) signaling are functionally related in extracellular matrix. Identification of TGFBR2 mutations in Marfan syndrome type II provided the direct evidence of the relation in humans. RECENT FINDINGS: More than 500 FBN1 mutations have been found in Marfan syndrome, tentative genotype - phenotype correlations have emerged, and mouse models are providing insight into pathogenic mechanisms. TGFBR2 mutations are still limited, however, in 2005 were also reported to cause a new aneurysm syndrome. Functional association between fibrillin-1 and TGF-beta signaling in extracellular matrix has been presented. SUMMARY: This review focuses on recent molecular genetics advances in Marfan syndrome and overlapping connective tissue disorders. Mutation spectrum of FBN1 and TGFBR2 in relation to phenotype is presented. Functional relation between fibrillin-1 and TGF-beta signaling is discussed. Future prospects in the study of Marfan syndrome are presented.

Animals↗

Heterozygous TGFBR2 mutations in Marfan syndrome.

Marfan syndrome is an extracellular matrix disorder with cardinal manifestations in the eye, skeleton and cardiovascular systems associated with defects in the gene encoding fibrillin (FBN1) at 15q21.1 (ref. 1). A second type of the disorder (Marfan syndrome type 2; OMIM 154705) is associated with a second locus, MFS2, at 3p25-p24.2 in a large French family (family MS1). Identification of a 3p24.1 chromosomal breakpoint disrupting the gene encoding TGF-beta receptor 2 (TGFBR2) in a Japanese individual with Marfan syndrome led us to consider TGFBR2 as the gene underlying association with Marfan syndrome at the MSF2 locus. The mutation 1524G-->A in TGFBR2 (causing the synonymous amino acid substitution Q508Q) resulted in abnormal splicing and segregated with MFS2 in family MS1. We identified three other missense mutations in four unrelated probands, which led to loss of function of TGF-beta signaling activity on extracellular matrix formation. These results show that heterozygous mutations in TGFBR2, a putative tumor-suppressor gene implicated in several malignancies, are also associated with inherited connective-tissue disorders.

Amino Acid Sequence↗

LRP5, low-density-lipoprotein-receptor-related protein 5, is a determinant for bone mineral density.

Osteoporosis is a multifactorial trait with low bone mineral density (BMD). We report results of an association study between BMD and nine candidate genes ( TGFB1, TGFBR2, SMAD2, SMAD3, SMAD4, IFNB1, IFNAR1, FOS and LRP5), as well as of a case-control study of osteoporosis. Samples for the former association study included 481 general Japanese women. Among the nine candidate genes examined, only LRP5 showed a significant association with BMD. We identified a strong linkage disequilibrium (LD) block within LRP5. Of five LPR5 single nucleotide polymorphisms (SNPs) that are located in the LD block, three gave relatively significant results: Women with the C/C genotype at the c.2220C>T SNP site had higher adjusted BMD (AdjBMD) value compared to those with C/T and T/T (p=0.022); and likewise, G/G at IVS17-30G>A and C/C women at c.3989C>T showed higher AdjBMD than those with G/A or A/A (p=0.039) and with C/T or T/T ( p=0.053), respectively. The case-control study in another series of samples consisting of 126 osteoporotic patients and 131 normal controls also gave a significant difference in allele frequency at c.2220C>T (kappa2=6.737, p=0.009). These results suggest that LRP5 is a BMD determinant and also contributes to a risk of osteoporosis.

Base Sequence↗