Nephrogenic diabetes insipidus (NDI) is an inherited disorder characterized by renal resistance to the antidiuretic effect of arginine vasopressin (AVP), resulting in polyuria, polydipsia, and hypoosmolar urine. In the vast majority of cases, NDI is associated with germ-line mutations in the vasopressin receptor type 2 gene (AVPR2) and in about 8% of the cases with the water channel aquaporin-2 gene (AQP-2) mutations. To date, approximately 277 families with 185 germ-line mutations in the AVPR2 gene have been described worldwide. In the present study, the AVPR2 gene was genotyped in eight unrelated Brazilian kindred with NDI. In five of these NDI families, novel mutations were noted (S54R, I130L, S187R, 219delT, and R230P), whereas three seemingly unrelated probands were found to harbor previously described AVPR2 gene mutations (R106C, R137H, R337X). Additionally a novel polymorphism (V281V) was detected. In conclusion, although NDI is a rare disease, the findings of mutations scattered over the entire coding region of the AVPR2 gene are a valuable model to determine structure function relationship in G-protein-coupled receptor related diseases. Furthermore, our data indicate that in Brazil the spectrum of AVPR2 gene mutations is "family specific".

According to WHO, suicide accounts for about 1,000,000 deaths worldwide every year. In view of these dramatic data, several studies have tried to identify possible biological mechanisms and markers of suicide. Genes encoding for proteins involved in the serotonergic transmission are major candidates in association studies of suicidal behavior. The gene that codes for tryptophan hydroxylase (TPH), the rate-limiting enzyme in the biosynthesis of serotonin, is one of these candidates. Two polymorphisms in intron 7 of this gene (A218C and A779C) have been described, but their role in suicidal behavior remains uncertain. TPH A218C polymorphism was analyzed in a sample of 248 psychiatric patients and 63 healthy controls. In addition, at least one close relative member was interviewed to assess family suicidal behavior history. Our research confirmed that a positive history of suicide attempts in a family member is associated with the chance of an individual to attempt suicide. Furthermore, we demonstrated that familial suicide attempts are more lethal and frequently more violent. We were not able to find significant differences of the TPH genotype frequencies between patients and controls. The TPH A218C genotypes were not associated with a history of suicide attempt and the lethality of the most lethal lifetime suicide attempt and suicide attempt method. The authors conclude that the A218C polymorphism of the TPH gene may not be a susceptibility factor for suicidal behavior in this group of psychiatric patients but confirm that a family suicidal behavior history increases the proband's suicide attempt risk.

Familial neurohypophysial diabetes insipidus (FNDI) is a rare autosomal dominant syndrome stemming from the absence of arginine vasopressin (AVP). More than thirty-five different germline mutations in the arginine vasopressin-neurophysin II gene have been reported. These mutations are either in the signal peptide or scattered throughout the neurophysin II domain. A missense mutation altering alanine at position -1 to either valine or threonine in the signal peptide domain has previously been found in ten unrelated families. In the present report, Brazilian female monozygotic twins with clinically typical central DI in whom biochemical and molecular characterization were carried out are described. Direct mutational analysis by sequencing of the vasopressin gene in germline DNA revealed a heterozygous missense mutation (G-->A) at nucleotide 279, predicting the substitution of alanine by threonine at position -1 of the signal peptide moiety. In summary, we present an extremely rare case of familial central diabetes insipidus in monozygotic Brazilian twins with a seemingly common missense mutation in the AVP gene.

Thiopurine methyltransferase (TPMT) catalyses the S-methylation of thiopurine drugs. Low-activity phenotypes are correlated with several mutations in the TPMT gene. Polymorphisms of TPMT have been reported for Caucasians, African-Americans and Asians. Since ethnic differences have been demonstrated worldwide, it remains to be elucidated in Brazil. The Brazilian population is the result of five centuries of interethnic crosses between peoples from almost all continents as well as autochthonous Amerindians, all forming the fifth largest and one of the most heterogeneous populations in the world. The frequency of six allelic variants of the TPMT gene, *2 (G238C) (2.2%), *3A (G460A and A719G) (1.5%), *3B (G460A) (0.2%), *3C (A719G) (1.0%), *5 (0%) and *6 (0%) were determined in Brazilian subjects using polymerase chain reaction (PCR)-RFLP and allele-specific PCR-based assays. This study provides the first analysis of TPMT mutant allele frequency in a sample of the Brazilian population.

BACKGROUND:Papillon-Lefévre syndrome (PLS) is a disorder that involves destruction of the periodontium and abnormal hyperkeratosis of the palms of the hands and soles of the feet. Mutations of the lysosomal protease cathepsin C gene (CTSC) have been associated with PLS. However, genotypic and phenotypic correlation has not been established. In the present study we investigated the CTSC gene in a Brazilian cohort affected by PLS.METHODS:Eight consanguineous members of a kindred with PLS were studied. DNA was extracted and all exons of the gene amplified by the polymerase chain reaction (PCR) using specific primers. Mutations were identified by DNA sequencing of the coding region and introns of the CTSC gene.RESULTS:Sequence analysis of CTSC from subjects affected by PLS identified a novel mutation (587T → C) in exon 4, predicted to cause a Leu196Pro amino acid substitution. Three of 3 subjects were homozygous for cathepsin C mutations inherited from a common ancestor. One patient was heterozygous and showed plantar hyperkeratosis without periodontal disease. Two other family members were also heterozygous but did not present palmoplantar hyperkeratosis and/or periodontal disease.CONCLUSIONS:This study describes a novel mutation of the cathepsin C gene in a Brazilian kindred with Papillon-Lefévre syndrome. J Periodontol 2002;73:307-312.

Craniopharyngioma is the most common childhood tumor and thought to arise from embryonic remnants of Rathke's pouch. The paucity of published data on the molecular basis of these tumors prompted us to examine 22 adamantinomatous craniopharyngiomas looking for genetic abnormalities. Using the X-linked polymorphic androgen receptor gene as a tool for X-chromosome inactivating analysis, we found that a subset of craniopharyngiomas are monoclonal and therefore are probably due to acquired somatic genetic defects. Thus, we investigated these tumours for mutations within three candidate genes, Gsα, Gi2α and patched (PTCH). Using single stranded conformational polymorphism (SSCP), denaturing gradient gel electrophoresis and direct sequencing, the presence of somatic mutations in these genes could not be demonstrated in any tumor. Our data indicate that a subset of craniopharyngiomas are monoclonal and the mutations in the PTCH, Gsα, and Gi2α contribute little if any to cranipharyngioma development.

I. Ozaki, Y. Yaegashi, T. Kimura, M. Baba, M. Matsunaga, I. Hashimoto (Japan) 41 Lysyl oxidase, the extracellular matrix-forming enzyme, in rat brain injury sites GM Gilad, HM Kagan, VH Gilad (Israel, USA) 45 Bisphenol-A differently affects estrogen receptors-a in estrous-cycling and lactating female rats AM Aloisi, D. Della Seta, I. Ceccarelli, F. Farabollini (Italy) 49 Peripheral capsaicin receptors increase in the inflamed rat hindpaw: a possible mechanism for peripheral sensitization SM Carlton, RE Coggeshall (USA) 53

Parathyroid adenomas are usually benign uniglandular tumors, and inactivation of several tumor suppressor genes, notably the MEN 1 gene, or activation of oncogenes have been implicated in the tumorigenesis. Genomic instability, indicative of the involvement of DNA mismatch repair genes, has not been previously described in parathyroid adenomas. A single large parathyroid adenoma was resected from an 8.5-yr-old Brazilian patient with no personal or family history of other endocrinopathies. Analysis of paired tumor-nontumor DNA using 23 microsatellite markers, located on chromosomes 1, 10, and 11 was carried out. Microsatellite instability was detected in nine markers (D1S191, D1S212, D1S413, D1S2848, RET, D11S901, D11S903, INSR, and INT2), whereas no allelic loss was detected with any of the analyzed markers. Immunohistochemical analysis of retinoblastoma protein expression revealed low levels of expression, but no histopathological signs of malignancy. We conclude that in this single, apparently sporadic parathyroid adenoma, DNA mismatch repair genes might be involved in parathyroid tumorigenesis.

An odontogenic keratocyst (OKC) is a benign cystic lesion of the jaws that occurs sporadically or in association with nevoid basal cell carcinoma syndrome (NBCCS). Recently, the gene for NBCCS was cloned and shown to be the human homologue of the Drosophila segment polarity gene Patched (PTCH), a tumor suppressor gene. The PTCH gene encodes a transmembrane protein that acts in opposition to the Hedgehog signaling protein, controlling cell fates, patterning, and growth in numerous tissues, including tooth. We investigated three cases of sporadic odontogenic keratocysts and three other cases associated with NBCCS, looking for mutations of the PTCH gene. Non-radioactive single-strand conformational polymorphism and direct sequencing of PCR products revealed a deletion of 5 base pairs (bp) in exon 3 (518delAAGCG) in one sporadic cyst as well as mutations in two cysts associated with NBCCS, a nonsense (C2760A) and a missense (G3499A) alteration. This report is the first to describe a somatic mutation of PTCH in sporadic odontogenic keratocysts as well as two novel mutations in cysts associated with NBCCS, indicating a similar pathogenesis in a subset of sporadic keratocysts.

BACKGROUNDMyxoma is a rare bone tumor of the mandible and maxillary sinus whose etiology and underlying molecular mechanisms remain unknown. Mutations that inhibit the GTPase activity of the a subunit of the stimulating G protein (Gsa) have been demonstrated in the myocardium of patients with McCune-Albright syndrome. The histopathological similarities shared by cardiac and jaw myxomas coupled with the paucity of reported candidate genes involved in jaw tumor pathogenesis, prompted us to investigate for the presence of gsp mutations in 23 sporadic jaw myxomas.MATERIALS AND METHODSWe used the polymerase chain reaction (PCR) to amplify the appropriate genomic fragments, followed by denaturing gradient gel electrophoresis (DGGE) analysis.RESULTSNo gsp mutations could be demonstrated in any of tumors analyzed, while the technique has a proven capability to detect these specific mutations.CONCLUSIONSWe conclude that mutations of the Gs alpha gene rarely, if ever, are associated with sporadic jaw myxomas tumorigenesis.

Objectives and Study Design: Squamous cell carcinomas are common malignancies and a major cause of mortality. The molecular mechanisms involved in tumorigenesis remain largely unknown, but sequence alterations have been identified in coding regions of several genes. Primary squamous cell carcinomas of various tissues (skin, head and neck, esophagus, lung, penis, uterus, and vagina) from 52 patients were analyzed for the presence of mutations within several candidate genes presumably involved in tumorigenesis: Gs alpha, Gi(2)alpha, GTPase activating protein (GAP), and patched (PTCH) genes. Methods: Mutational analysis scheme included polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), single stranded conformational polymorphism (SSCP), and selected sequence analysis. Results and Conclusion: No tumor had any evidence of mutations in any of these analyzed genes. Mutations within these genes do not occur frequently in an unselected population of patients with squamous cell carcinomas.

Nephrogenic diabetes insipidus is a rare hereditary disorder, most commonly transmitted in an X chromosome-linked recessive manner and characterized by the lack of renal response to the action of antidiuretic hormone [Arg8]vasopressin. The vasopressin type 2 receptor (V2R) has been suggested to be the gene that causes the disease, and its role in disease pathogenesis is supported by mutations within this gene in affected individuals. Using the PCR, denaturing gradient gel electrophoresis, and direct DNA sequencing, we examined the V2R gene in four unrelated kindreds. In addition, linkage analysis with chromosome Xq28 markers was done in one large Brazilian kindred with an apparent unusual X chromosome-linked dominant inheritance pattern. In one family, a mutation in codon 280, causing a Tyr-->Cys substitution in the sixth transmembrane domain of the receptor, was found. In the other three additional families with nephrogenic diabetes insipidus, the V2R-coding region was normal in sequence. In one large Brazilian kindred displaying an unusual X chromosome-linked dominant mode of inheritance, the disease-related gene was localized to the same region of the X chromosome as the V2R, but no mutations were found, thus raising the possibility that this disease is caused by a gene other than V2R.