Biomedical subjects

E V Semina

Publications and source records attributed to E V Semina.

23 records · Page 2Linked to original sources

PubMed1998

Mutation in the RIEG1 gene in patients with iridogoniodysgenesis syndrome.

Axenfeld-Rieger syndrome (ARS) and iridogoniodysgenesis syndrome (IGDS) are clinically related autosomal dominant disorders which affect the anterior segment of the eye as well as non-ocular structures. ARS patients present with iris hypoplasia, a prominent Schwalbe line, adhesions between the iris stroma and the iridocorneal angle and increased intraocular pressure. IGDS is characterized by iris hypoplasia, goniodysgenesis and increased intraocular pressure. Each syndrome also presents with non-ocular features including maxillary hypoplasia, micro and anodontia, redundant periumbilical skin, hypospadius (in males), and each has been genetically linked to chromosome 4q25. RIEG1 , the gene responsible for the 4q25 ARS phenotype, recently has been cloned. RIEG1 encodes a novel member of the bicoid class of homeobox proteins known to be active as transcription factors. Mutational analysis has previously detected several mutations in this gene in ARS individuals. We have now detected a mutation in RIEG1 which segregates with the disease phenotype in a family with IGDS. This mutation is a G-->A transition altering an arginine residue to a histidine in a highly conserved location in the second helix of the homeobox of RIEG1. This mutation indicates that IGDS and ARS are allelic variants of the same disorder. This wide variability in clinical consequences of mutations at the RIEG1 4q25 locus implicates the RIEG gene broadly in ocular and craniofacial disorders.

Adolescent↗

PubMed1997

Isolation of a new homeobox gene belonging to the Pitx/Rieg family: expression during lens development and mapping to the aphakia region on mouse chromosome 19.

We recently reported the positional cloning of a homeobox gene involved in the pathogenesis of Rieger syndrome, RIEG1 , and its mouse homolog, Rieg1 . Rieg1 (also independently described as Pitx2) is highly homologous to the Ptx1/Potx gene product, suggesting that there may be additional members of this novel Pitx family. The Pitx genes play an important role in eye, tooth, pituitary and umbilical region development as evidenced by Rieger syndrome and iris hypoplasia phenotypes, resulting from mutations in the RIEG1 gene and by expression studies. In order to characterize further the Pitx gene family we searched mouse cDNA libraries to identify additional members. A new gene was isolated which encodes a homeoprotein with strong homology to the other Pitx proteins and 97-100% identity in the homeodomain itself, suggesting that this is a third member of the family, Pitx3 . In whole mount in situ hybridization on mouse embryos ranging from 8.5 to 11.5 days post-coitum (d.p.c.), Pitx3 mRNA was seen only in the developing lens starting at day 11. Hybridization on cross-sections revealed strong signals in the lens vesicle in 11 d.p.c. embryos and throughout the lens, particularly in the anterior epithelium and equator region in 15 d.p.c. embryos. Pitx3 was mapped close to aphakia on mouse chromosome 19. The aphakia homozygous mouse is characterized by small eyes lacking a lens, which fail to develop beyond 11 d.p.c. These data make Pitx3 a strong candidate gene for the aphakia phenotype in the mouse and suggest a role for the human homolog in congenital lens malformations.

Amino Acid Sequence↗

PubMed1996

Cloning and characterization of a novel bicoid-related homeobox transcription factor gene, RIEG, involved in Rieger syndrome.

Rieger syndrome (RIEG) is an autosomal-dominant human disorder that includes anomalies of the anterior chamber of the eye, dental hypoplasia and a protuberant umbilicus. We report the human cDNA and genomic characterization of a new homeobox gene, RIEG, causing this disorder. Six mutations in RIEG were found in individuals with the disorder. The cDNA sequence of Rieg, the murine homologue of RIEG, has also been isolated and shows strong homology with the human sequence. In mouse embryos Rieg mRNA localized in the periocular mesenchyme, maxillary and mandibular epithelia, and umbilicus, all consistent with RIEG abnormalities. The gene is also expressed in Rathke's pouch, vitelline vessels and the limb mesenchyme. RIEG characterization provides opportunities for understanding ocular, dental and umbilical development and the pleiotropic interactions of pituitary and limb morphogenesis.

Abnormalities, Multiple↗

PubMed1996

Exclusion of epidermal growth factor and high-resolution physical mapping across the Rieger syndrome locus.

We have evaluated the 4q25-4q26 region where the autosomal dominant disorder Rieger syndrome has been previously mapped by linkage. We first excluded epidermal growth factor as a candidate gene by carrying out SSCP analysis of each of its 24 exons using a panel of seven unrelated individuals with Rieger syndrome. No evidence for etiologic mutations was detected in these individuals, although four polymorphic variants were identified, including three that resulted in amino acid changes. We next made use of two apparently balanced translocations, one familial and one sporadic, to identify a narrow physical localization likely to contain the gene or to be involved in regulation of gene function. Somatic cell hybrids were established from individuals with these balanced translocations, and these hybrids were used as a physical mapping resource for, first, preliminary mapping of the translocation breakpoints using known sequence tagged sites from chromosome 4 and then, after creating YAC and cosmids contigs encompassing the region, for fine mapping of those breakpoints. A cosmid contig spanning these breakpoints was identified and localized the gene to within approximately 150 kb of D4S193 on chromosome 4. The interval between the two independent translocations is approximately 50 kb in length and provides a powerful resource for gene identification.

Chromosome Mapping↗

PubMedDate not supplied

Assignment of gene responsible for progressive pseudorheumatoid dysplasia to chromosome 6 and examination of COL10A1 as candidate gene.

Progressive pseudorheumatoid dysplasia is an autosomal recessive skeletal dysplasia with radiographic changes in the spine similar to Spondyleopiphyseal dysplasia tarda and clinical, though not radiographic resemblance to rheumatoid arthritis. About two-thirds of the reported patients are of Arabic and Mediterranean origin which reflects the relative high incidence in this population. We performed homozygosity mapping utilising the DNA pooling approach to map progressive pseudorheumatoid dysplasia to a chromosomal region on the long arm of chromosome 6. We examined a possible candidate gene in the same region of linkage, namely COL10A1, for alterations in this disorder. We did not identify any mutations in our family, but did not totally exclude COL10A1 gene from being the disease-causing gene.

Base Sequence↗