The 46, XX disorder of sex development (DSD) is a rare form of sex reversal in infertile men, that was first described by la Chapelle et al. in 1964 and occurred 1:20 000 in newborns. Usually, it is caused by unequal crossingover between X and Y chromosomes during meiosis in the father, which results in the X chromosome containing the normally-male SRY gene. When this X combines with a normal X...

The 46 XX, testicular sex differentiation disorder, or XX male syndrome, is a rare condition detected by cytogenetics, in which testicular development occurs in the absence of the Y chromosome. It occurs in 1:20,000 to 25,000 male newborns and represents 2% of cases of male infertility. About 90% of individuals present with normal phenotype at birth and are generally diagnosed after puberty for...

A baby girl with some of the stigmata of Down's syndrome was found to be a mosaic with three different cell lines: 45,XX,-13,-21,+t(13q21q)/(46,XX/46,XX, -21,+t(21q21q). The chromosome rearrangements detected in this patient appear to have arisen de novo. In the normal cell line the terminal end of the p arm of one chromosome 21 is thought to have been damaged. It seems probable that this is re...

BACKGROUND Chromosomal abnormalities contribute substantially to reproductive problems, but the role of environmental risk factors has received little attention. OBJECTIVES We evaluated the association of polychlorinated biphenyl (PCB) and dichlorodiphenyldichloroethylene (p,p'-DDE) exposures with sperm sex-chromosome disomy. METHODS We conducted a cross-sectional study of 192 men from subf...

Chick cDNA clones for a new member of the FACIT (fibril-associated collagens with interrupted triple helices) subfamily have been isolated and sequenced. The collagen chain encoded by these cDNAs was assigned the next consecutive number, making it the alpha1(XX) collagen chain. Assignment of type XX collagen to the FACIT family was based on sequence similarities to types XII and XIV collagen. T...

Blow-up phenomena are analyzed for both the delay-differential equation (DDE) u(t) = B(t)u(t− τ), and the associated parabolic PDE (PDDE) ∂tu = ∆u+B (t)u(t− τ, x), where B : [0, τ ] → R is a positive L function which behaves like 1/ |t− t∗| , for some α ∈ (0, 1) and t∗ ∈ (0, τ). Here B′ represents its distributional derivative. For initial functions satisfying u(t∗ − τ) > 0, blow up takes place...

and Applied Analysis 3 Differentiating (14) with respect to xx yields dd dddd ppxx = (mm m m) uu uuxx 󶀡󶀡ddt pp󶀱󶀱 ppxxt dd t [0t TT) t ppxx (0t xx) = mt (15)

BACKGROUND SOX9 is a widely expressed transcription factor playing several relevant functions during development and essential for testes differentiation. It is considered to be the direct target gene of the protein encoded by SRY and its overexpression in an XX murine gonad can lead to male development in the absence of Sry. Recently, a family was reported with a 178 kb duplication in the gene...

Differentiation of mouse embryonic germ cells as male or female is dependent on the somatic environment of the gonad rather than the sex chromosome constitution of the germ cell. However, little is known about the initiation of germ cell sexual differentiation. Here, we traced the initiation of germ cell sexual differentiation in XX gonads using the Stra8 gene, which we demonstrate is an early ...