title: Caudal dysgenesis, sirenomelia, and situs inversus totalis: a primitive defect in blastogenesis.
abstract: Caudal dysgenesis (CD) constitutes a heterogeneous spectrum of congenital caudal anomalies, including varying degrees of agenesis of the vertebral column, as well as anorectal and genitourinary anomalies. Sirenomelia, characterized by a fusion of the lower limbs, could represent the most severe end of this spectrum. The two main debated pathogenic hypotheses are an aberrant vascular supply versus a primary axial mesoderm defect. We present the autopsy findings of two fetuses of non-diabetic mothers, with normal karyotype. Both fetuses presented situs inversus associated with a CD, in one case consisting of sirenomelia, establishing a very rare association profile that might be random. This association also suggests the occurrence of a common pathogenic mechanism, in accordance to recent genetic data, such as displayed in the Kif3A murine mutation phenotype. Some cases of sirenomelia and CD could represent developmental field defects of blastogenesis involving the caudal mesoderm, rather than being related to vascular insufficiency.
authors.affiliation: Department of Pathology, CHU Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Rougemont
authors.forename: Dorothée
authors.initials: D
authors.lastname: Bouron-Dal Soglio
authors.forename: Valérie
authors.initials: V
authors.lastname: Désilets
authors.forename: Mubina
authors.initials: M
authors.lastname: Jovanovic
authors.forename: Gilles
authors.initials: G
authors.lastname: Perreault
authors.forename: Luc
authors.initials: L
authors.lastname: Laurier Oligny
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Fournet
mesh_terms: D037881:Aborted Fetus / Q000002:abnormalities*; D004480:Ectromelia / Q000196:embryology*; D047109:Fetal Development; D006801:Humans; D012857:Situs Inversus / Q000196:embryology*; D013131:Spine / Q000002:abnormalities; D016216:Ultrasonography, Prenatal; D014564:Urogenital Abnormalities / Q000196:embryology