Biomedical subjects

Catheline Vilain

Publications and source records attributed to Catheline Vilain.

4 recordsLinked to original sources

PubMed2007

Nephrogenic syndrome of inappropriate antidiuresis in adults: high phenotypic variability in men and women from a large pedigree.

Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a recently described genetic cause of hyponatremia in male infants. Whether this X-linked condition could be detected in the adult or also could affect women is unknown. A large five-generation family was identified in which the recently described arginine-vasopressin receptor type 2 (AVPR2) mutation that is responsible for NSIAD was segregated. The proband was a 74-yr-old patient who had a syndrome of inappropriate antidiuresis and whose hyponatremia resisted administration of two AVPR2 antagonists. The phenotype of family members who carry the mutation was investigated. Patients with normal serum sodium were subjected to a water-load test. The previously reported activating missense R137C mutation in the AVPR2 gene in three hemizygous male and four heterozygous female individuals was identified. Except in one woman, spontaneous episodes of hyponatremia or abnormal water-load test were identified in all patients with the mutation, whether male or female. Skewed X inactivation was evidenced in the blood of the asymptomatic woman, which is compatible with preferential inactivation of her mutated allele. NSIAD is not limited to male infants. The diagnosis also should be considered in both male and female adults.

Adult↗

PubMed2004

Characterization of a novel loss of function mutation of PAX8 in a familial case of congenital hypothyroidism with in-place, normal-sized thyroid.

Thyroid dysgenesis is the most common cause of congenital hypothyroidism, a relatively frequent disease affecting 1 in 3000-4000 newborns. Whereas most cases are sporadic, mutations in transcription factors implicated in thyroid development have been shown to cause a minority of cases transmitted as monogenic Mendelian diseases. PAX8 is one of these transcription factors, and so far, five mutations have been identified in its paired domain in patients with thyroid dysgenesis. We have identified a novel mutation of PAX8, in the heterozygous state, in a father and his two children both presenting with congenital hypothyroidism associated with an in-place thyroid of normal size at birth. In addition, one of the affected siblings displayed unilateral kidney agenesis. The mutation substitutes a highly conserved serine in position 54 of the DNA-binding domain of the protein (S54G mutation) by a glycine. Functional analyses of the mutant protein (PAX8-S54G) demonstrated that it is unable to bind a specific cis-element of the thyroperoxidase gene promoter in EMSAs and that it has almost completely lost the ability to act in synergy with Titf1 to transactivate transcription from the thyroglobulin promoter/enhancer. These results indicate that loss of function mutations of the PAX8 gene may cause congenital hypothyroidism in the absence of thyroid hypoplasia.

Amino Acid Sequence↗

PubMed2004

Small amplified RNA-SAGE.

Serial analysis of gene expression (SAGE) is a powerful genome-wide analytic tool to determine expression profiles. Since its description in 1995 by Victor Velculescu et al., SAGE has been widely used. Recently, the efficiency of the method has been emphasized as a means to identify novel transcripts or genes that are difficult to identify by conventional methods. SAGE is based on the principle that a 10-base pair (bp) cDNA fragment contains sufficient information to unambiguously identify a transcript, provided it is isolated from a defined position within this transcript. Concatenation of these sequence tags allows serial analysis of transcripts by sequencing multiple tags within a single clone. Extraction of sequence data by computer programs provides a list of sequence tags that reflect both qualitatively and quantitatively the gene expression profile. Several modifications to the initial protocol allowed to start from 1 microg total RNA (or 10(5) cells). In order to reduce the amount of input RNA, protocols including extra polymerase chain reaction (PCR) steps were designed. Linear amplification of the mRNA targets might have advantage over PCR by minimizing biases introduced by the amplification step; therefore we devised a SAGE protocol in which a loop of linear amplification of RNA has been included. Our approach, named "small amplified RNA-SAGE" (SAR-SAGE) included a T7 RNA polymerase promoter within an adapter derived from the standard SAGE linker. This allowed transcription of cDNA segments, extending from the last NlaIII site of transcripts to the polyA tail; these small amplified RNAs then serve as template in a classical (micro)SAGE procedure. As the cDNAs are immobilized on oligo(dT) magnetic beads, several rounds of transcription can be performed in succession with the same cDNA preparation, with the potential to increase further the yield in a linear way. Except for the transcription step itself, the present procedure does not introduce any extra enzymatic reaction in the classical SAGE protocol, it is expected to keep the representation biases associated with amplification as low as possible.

Animals↗

PubMed2003

Small amplified RNA-SAGE: an alternative approach to study transcriptome from limiting amount of mRNA.

Serial analysis of gene expression (SAGE) is a widely used and powerful technique to characterize and compare transcriptomes. Although several modifications have been proposed to the initial protocol with the aim of reducing the amount of starting material, unless additional PCR steps are added, the technique is still limited by the need for at least 1 micro g of total RNA. As extra PCR amplification might introduce representation biases, current SAGE protocols are not fully suitable for the study of small, microdissected tissue samples. We propose here an alternative method involving the linear amplification of small mRNA fragments containing the SAGE tags. The procedure allows preparation of libraries of over 100 000 tags from as few as 2500 cells. A satisfactory correlation was observed between a microSAGE library made from 5 microg of total thyroid RNA, and a library prepared from 50 ng of the same RNA preparation according to the present protocol.

Animals↗