Keio University · Biochemistry, Genetics and Molecular Biology
Professor Kenjiro Kosaki's research lab specializes in clinical and molecular genetics, with a focus on neurodevelopmental and congenital disorders, including Noonan syndrome, Shprintzen-Goldberg syndrome, and imprinting disorders such as Prader-Willi and Angelman syndromes. The lab employs advanced molecular techniques—such as denaturing HPLC, direct sequencing, and bisulfite-based methylation analysis—to identify disease-causing mutations and epigenetic alterations. A key research direction involves understanding the genetic and epigenetic mechanisms underlying chromosomal abnormalities, mosaicism, and complex multisystem disorders, particularly in pediatric populations.
Figures are computed from collected data and may differ slightly.
Noonan syndrome is an autosomal dominant disorder defined by short stature, delayed puberty, and characteristic dysmorphic features. Tartaglia et al. (Nature Genetics, 29:465-468) have recently shown that gain-of-function mutations in the gene PTPN11 (protein-tyrosine phosphatase, nonreceptor-type 11) cause Noonan syndrome in roughly half of patients that they examined. To further explore the relevance of PTPN11 mutations to the pathogenesis of Noonan syndrome, we analyzed the PTPN11 gene in 21
Editor's Note In the following paper the authors report on two patients with Shprintzen-Goldberg syndrome (SGS): one with an FBN1 mutation and the other having a disease-causing mutation of TGFRB2. The observation of these two patients with mutations of different genes and the documentation of other patients without mutations of either gene suggest that SGS is causally heterogeneous. This paper was presented as a poster at the 2005 meeting of the American Society of Human Genetics in Salt Lake C
We document a sib pair born to a mother with a reciprocal translocation, t(15;22)(q13;q11.2): the daughter had the Angelman syndrome phenotype associated with a maternally derived 15q deletion, and the son had a phenotype associated with a 22q deletion. Adjacent two-type segregation during gametogenesis in the mother can account for the unbalanced karyotypes of the siblings. From a tetravalent chromatid formed by normal chromosome 15, derivative chromosome 15, normal chromosome 22, and derivativ
The putative promoter region of the SNRPN gene contains a CpG island which is heavily methylated in the maternally derived allele and unmethylated in the paternally derived allele. In patients with Prader-Willi syndrome (PWS) only the methylated allele is present, while in those with Angelman syndrome (AS) only the unmethylated allele is present. The purpose of this paper is to report a polymerase chain reaction (PCR)-based assay to evaluate methylation status of the CpG island of the SNRPN gene
Moyamoya disease is characterized by diffuse distal intracranial stenosis. Recently, RNF213 has been identified as a susceptibility gene in the development of this condition. Pulmonary hypertension is a rare progressive vasculopathy with an unknown etiology. The co-occurrence of pulmonary hypertension and Moyamoya disease has been described in four patients; however, whether this co-occurrence represents a chance association or a common vascular pathology has remained unknown. Here, we report tw
Gonadal mosaicism represents an underappreciated feature of the inheritance pattern of CdLS. To our knowledge, the girl represents the first CdLS patient whose father was documented to have a population of mutant sperm. When a sperm analysis indicates the presence of a mutant allele, it may be reasonable to offer prenatal genetic testing to the family in subsequent pregnancies, given that the sensitivity of fetal ultrasonography is relatively low.
We investigated preliminarily whether methylenetetrahydrofolate reductase (MTHFR) 677C/T or reduced folate carrier 1 (RFC1) 80G/A polymorphisms were associated with toxicities during maintenance chemotherapy with mercaptopurine (6MP) and methotrexate (MTX) in children with acute lymphoblastic leukemia or lymphoblastic lymphoma. The clinical records of 20 children (2 to 15-y old) who had received maintenance chemotherapy were reviewed retrospectively and their genomic DNA was genotyped to identif
We report a family in which a healthy, unrelated couple had a male fetus with bilateral ventriculomegaly, a normal liveborn girl, a hydatidiform molar pregnancy, a female fetus with ventriculomegaly and situs abnormalities, and a male fetus with hydrocephalus, a three-lobed left lung, and defective tracheal cilia with absent inner dynein arms and a single centriole. A mutation analysis of FOXJ1 and POLL in the last fetus with ciliary defect revealed no mutation within their coding regions. The p
Hox genes play a critical role in morphogenesis of the early embryo along the anteroposterior axis. In mammals, 39 Hox genes with extensive homology are organized into 13 paralogous groups, forming four clusters on four separate chromosomes. The genes within each cluster are arranged in a 3' to 5' direction and expressed in a temporally and spatially coordinated manner along the anteroposterior axis in the vertebrae, limbs and viscera, including the gastrointestinal tract, but little is known ab
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