[Show abstract][Hide abstract] ABSTRACT: Sexual development in mammals is based on a complicated and delicate network of genes and hormones that have to collaborate in a precise manner. The dark side of this pathway is represented by pathological conditions, wherein sexual development does not occur properly either in the XX and the XY background. Among them a conundrum is represented by the XX individuals with at least a partial testis differentiation even in absence of SRY. This particular condition is present in various mammals including the dog. Seven dogs characterized by XX karyotype, absence of SRY gene, and testicular tissue development were analysed by Array-CGH. In two cases the array-CGH analysis detected an interstitial heterozygous duplication of chromosome 9. The duplication contained the SOX9 coding region. In this work we provide for the first time a causative mutation for the XXSR condition in the dog. Moreover this report supports the idea that the dog represents a good animal model for the study of XXSR condition caused by abnormalities in the SOX9 locus.
PLoS ONE 01/2014; 9(7):e101244. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In-frame mis-sense and splicing mutations (resulting in a 2 amino acid insertion or a 34 amino acid deletion) dispersed through the MAP3K1 gene tilt the balance from the male to female sex-determining pathway, resulting in 46,XY disorder of sex development (DSD). These MAP3K1 mutations mediate this balance by enhancing WNT/β-catenin/FOXL2 expression and β-catenin activity and by reducing SOX9/FGF9/FGFR2/SRY expression. These effects are mediated at multiple levels involving MAP3K1 interaction with protein co-factors and phosphorylation of downstream targets. In transformed B-lymphoblastoid cell lines and NT2/D1 cells transfected with wild type or mutant MAP3K1 cDNAs under control of the constitutive CMV promoter, these mutations increased binding of RHOA, MAP3K4, FRAT1 and AXIN1 and increased phosphorylation of p38 and ERK1/2. Overexpressing RHOA or reducing expression of MAP3K4 in NT2/D1 cells produced phenocopies of the MAP3K1 mutations. Using siRNA knockdown of RHOA or overexpressing MAP3K4 in NT2/D1 cells produced anti-phenocopies. Interestingly, the effects of the MAP3K1 mutations were rescued by co-transfection with wild type MAP3K4. Although MAP3K1 is not usually required for testis-determination, mutations in this gene can disrupt normal development through the gains of function demonstrated in this study.
Human Molecular Genetics 10/2013; · 7.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplasia. Mutations in either ENG or ACVRL1 account for around 85% of cases, and 10% are large deletions and duplications. Here we present a large novel deletion in ACVRL1 gene and its molecular characterization in a 3 generation Italian family. We employed short tandem repeats (STRs) analysis, direct sequencing, multiplex ligation-dependant probe amplification (MLPA) analysis, and 'deletion-specific' PCR methods. STRs Analysis at ENG and ACVRL1 loci suggested a positive linkage for ACVRL1. Direct sequencing of this gene did not identify any mutations, while MLPA identified a large deletion. These results were confirmed and exactly characterized with a 'deletion-specific' PCR: the deletion size is 4,594 bp and breakpoints in exon 3 and intron 8 show the presence of short direct repeats of 7 bp [GCCCCAC]. We hypothesize, as causative molecular mechanism, the replication slippage model. Understanding the fine mechanisms associated with genomic rearrangements may indicate the nonrandomness of these events, highlighting hot spots regions. The complete concordance among MLPA, STRs analysis and 'deletion-specific PCR' supports the usefulness of MLPA in HHT molecular analysis.
[Show abstract][Hide abstract] ABSTRACT: Gonadal cellular organization is very similar in all vertebrates, though different processes can trigger bipotential gonads to develop into either testes or ovaries. While mammals and birds, apart from some exceptions, show genetic sex determination (GSD), other animals, like turtles and crocodiles, express temperature-dependent sex determination. In some groups of animals, GSD can also be overridden by hormone or temperature influences, indicating how fragile this system can be. This review aims to explain the fundamental molecular mechanisms involved in mammalian GSD, mainly referring to mouse as a major model. Conceivably, other mammals might show a molecular mechanism different from the commonly investigated murine species.
Sexual Development 01/2012; 6(1-3):7-17. · 2.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report the case of a child with clinical and haematological features indicative of juvenile myelomonocytic leukaemia (JMML). The patient showed dysmorphic features: high forehead, bilateral epicanthal folds, long eyebrows, low nasal bridge and slightly low-set ears. A 38G>A (G13D) mutation in exon 1 of the NRAS gene was first demonstrated on peripheral blood cells, and then confirmed on granulocyte-macrophage colony-forming units. The same mutation was also found in buccal swab, hair bulbs, endothelial cells, skin fibroblasts. This case suggests for the first time that constitutional mutations of NRAS may be responsible for development of a myeloproliferative/myelodysplastic disorder in children.
British Journal of Haematology 09/2009; 147(5):706-9. · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The association of abnormal chromosome constitutions and disorders of sex development in domestic animals has been recorded since the beginnings of conventional cytogenetic analysis. Deviated karyotypes consisting of abnormal sex chromosome sets (e.g. aneuploidy) and/or the coexistence of cells with different sex chromosome constitutions (e.g. mosaicism or chimerism) in an individual seem to be the main causes of anomalies of sex determination and sex differentiation. Molecular cytogenetics and genetics have increased our understanding of these pathologies, where human and mouse models have provided a substantial amount of knowledge, leading to the discovery of a number of genes implicated in mammalian sex determination and differentiation. Additionally, other genes, which appeared to be involved in ovary differentiation, have been found by investigations in domestic species such as the goat. In this paper, we present an overview of the biology of mammalian sex development as a scientific background for better understanding the body of knowledge of the clinical cytogenetics of disorders of sex development in domestic animals. An attempt to summarize of what has been described in that particular subject of veterinary medicine for each of the main mammalian domestic species is presented here.
Cytogenetic and Genome Research 01/2009; 126(1-2):110-31. · 1.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Up to now, two loci have been involved in XX sex-reversal in mammals following loss-of-function mutations, PIS (Polled Intersex Syndrome) in goats and R-spondin1 (RSPO1) in humans. Here, we analyze the possible interaction between these two factors during goat gonad development. Furthermore, since functional redundancy between different R-spondins may influence gonad development, we also studied the expression patterns of RSPO2, 3 and 4.
Similarly to the mouse, RSPO1 shows a sex-dimorphic expression pattern during goat gonad development with higher levels in the ovaries. Interestingly, the PIS mutation does not seem to influence its level of expression. Moreover, using an RSPO1 specific antibody, the RSPO1 protein was localized in the cortical area of early differentiating ovaries (36 and 40 dpc). This cortical area contains the majority of germ cell that are surrounded by FOXL2 negative somatic cells. At latter stages (50 and 60 dpc) RSPO1 protein remains specifically localized on the germ cell membranes. Interestingly, a time-specific relocation of RSPO1 on the germ cell membrane was noticed, moving from a uniform distribution at 40 dpc to a punctuated staining before and during meiosis (50 and 60 dpc respectively). Interestingly, also RSPO2 and RSPO4 show a sex-dimorphic expression pattern with higher levels in the ovaries. Although RSPO4 was found to be faintly and belatedly expressed, the expression of RSPO2 increases at the crucial 36 dpc stage, as does that of FOXL2. Importantly, RSPO2 expression appears dramatically decreased in XX PIS-/- gonads at all three tested stages (36, 40 and 50 dpc).
During goat ovarian development, the pattern of expression of RSPO1 is in agreement with its possible anti-testis function but is not influenced by the PIS mutation. Moreover, our data suggest that RSPO1 may be associated with germ cell development and meiosis. Interestingly, another RSPO gene, RSPO2 shows a sex-dimorphic pattern of expression that is dramatically influenced by the PIS mutation.
[Show abstract][Hide abstract] ABSTRACT: R-spondins are a recently characterized small family of growth factors. Here we show that human R-spondin1 (RSPO1) is the gene disrupted in a recessive syndrome characterized by XX sex reversal, palmoplantar hyperkeratosis and predisposition to squamous cell carcinoma of the skin. Our data show, for the first time, that disruption of a single gene can lead to complete female-to-male sex reversal in the absence of the testis-determining gene, SRY.
[Show abstract][Hide abstract] ABSTRACT: Sex determination in mammals is based on a genetic cascade that controls the fate of the gonads. Gonads will then direct the establishment of phenotypic sex through the production of hormones. Different types of sex reversal are expected to occur if mutations disrupt one of the three steps of gonadal differentiation: formation of the gonadal primordia, sex determination, and testis or ovary development.
Current Opinion in Genetics & Development 07/2006; 16(3):289-92. · 7.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The association of palmoplantar keratoderma (PPK) with the development of cutaneous squamous cell carcinomas (SCCs), dental anomalies, severe hypogenitalism with hypospadias, abnormal development of gonads with ambiguous external genitalia, gynecomastia, altered plasma sex hormones levels, and hypertriglyceridemia has not, to our knowledge, been reported previously. We describe it in 4 brothers with 46,XX karyotype, whereas the 5 sisters of their consanguineous parents were unaffected. This family may represent a new syndrome. The PPK was of the classical nonepidermolytic histologic type. The proband also had a laryngeal carcinoma diagnosed in his early forties and nodular testicular hyperplasia of Leydig cells.
Journal of the American Academy of Dermatology 12/2005; 53(5 Suppl 1):S234-9. · 4.91 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We describe a large inbred Sicilian family that includes four 46, XX (SRY-) brothers. Palmoplantar hyperkeratosis (PPK) and an associated predisposition to squamous cell carcinoma (SCC) of the skin, segregates as a recessive trait within the family. Interestingly, all the PPK-affected members of the family are phenotypic males (46,XY or 46,XX) while seven XX sibs are healthy phenotypic females with no signs of PPK. We propose that homozygosity for a single mutational event, possibly including contiguous genes, may cause PPK/SCC in both XY or XX individuals and sex reversal in XX individuals. The family is informative for linkage analysis for the PPK trait and allows linkage exclusion for the sex reversal trait. Here we show that 15 loci involved in PPK etiology, skin differentiation, function or malignancy, and nine loci involved in sex determination/differentiation are not implicated in the phenotype of this family.
American Journal of Medical Genetics Part A 11/2005; 138A(3):241-6. · 2.30 Impact Factor