Disturbances Of Embryonic Development Research Articles

042. Colonic Duplication with Recto-Vestibular Fistula: A Case Report

Background: Anorectal malformations associated with colonic duplications are a rare condition. Colonic duplication may have different presentations according to its location and size, with an incidence of less than 15% of all gastrointestinal duplications. Colonic duplication is less common than ileal duplication, whether cystic or tubular. Duplications are considered congenital malformations because they are thought to arise from disturbances in embryonic development. This report aims to present and analyze the clinical presentation, diagnostic approach, and management of anorectal malformations associated with colonic duplications in an 11-month-old child at our hospital, highlighting the challenges and treatment strategies for such a rare case. Case: We present a case of an 11-month-old girl, referred from a network hospital with a post-colostomy at 4 months of age for recto-vestibular fistula with findings of colonic duplications at colostomy. Exploratory laparotomy was performed until the colonic duplications were identified and completely resected. Conclusion: Colonic duplication is a rare congenital disorder, and its association with anorectal abnormalities is even rarer. The surgical treatment includes resection of the duplicated colon. Surgical intervention is the treatment of choice.

Variable expressivity of TCTEX1D2 mutations and a possible pathogenic link of molar-incisor malformation to ciliary dysfunction

ObjectiveClarification of the molecular basis of a ciliopathy associated with molar-incisor malformation in a consanguineous Turkish family. DesignFull dental and clinical examinations, histologic analysis, comprehensive genetic analyses including exome sequencing, ciliary function tests and transmission electron microscopy of ciliary biopsies in the surviving patient. ResultsTwo siblings had situs inversus and complex heart defects suggestive of ciliary dysfunction. The affected girl who died in utero showed severe chest abnormalities compatible with Jeune syndrome which were not present in the affected boy. Dental investigations in the boy showed typical signs of molar-incisor-malformation. Exome sequencing identified a homozygous intragenic deletion in TCTEX1D2 which is predicted to completely remove protein function. Ciliary function tests and electron microscopy showed mild irregularities of motile cilia such as compound cilia and loss of membranes. ConclusionsOur findings support the suggestion that TCTEX1D2 mutations have variable expressivity and may be associated with disturbances of embryonic development caused by both, ciliary signaling and motile dysfunction. The presence of molar-incisor-malformation in the living patient raises the possibility of a pathogenetic link of this rare dental anomaly to ciliary dysfunction during tooth development at least in some individuals.

Fatty acid and carotenoid composition of eggs from two nonanadromous Atlantic salmon stocks of cultured and wild origin

Two Swedish landlocked (nonanadromous) salmon (Salmo salar) stocks were investigated with the aim of characterising their egg fatty acid (FA) and carotenoid profiles. Fish from one of the stocks were also cultured over the past few decades as part of the Swedish program for genetic preservation, allowing a comparison between the eggs from females on a diet based on lipids of limnic (natural food chain) origin and eggs from females fed an artificial diet of marine origin. No significant differences in the FA profile of the phospholipid (PL) or triacylglycerol (TAG) fraction were found between the two wild stocks. The content of EPA (20:5n-3, eicosapentaenoic acid) in PL fraction was significantly higher in eggs from cultured females (13.0%) compared with eggs from both wild stocks (5.7 and 6.4%). Further, in PL fraction, AA (20:4n-6, arachidonic acid) levels in these eggs were significantly lower (2.4% versus 6.7 and 6.2%). The AA content of the TAG fraction differed greatly between wild (4.4 and 4.9%) and cultured (1.2%) eggs, whereas this fraction showed almost no corresponding difference in EPA content. The level of DHA (22:6n-3, docosahexaenoic acid) did not differ between the two wild stocks or between wild and cultured fish. This was in spite of widely different levels of DHA in the diet. The composition of carotenoids was altered in the cultured eggs which had a higher proportion and higher content (1.16 μ g egg−1) of astaxanthin than the wild eggs (0.56 and 0.62 μg egg−1, respectively). Hatching success varied markedly between wild (>95%) and cultured fish (40–75%). We conclude that changes in the lipid source in the diet of female salmon during gonadal maturation will alter the egg fatty acid composition with an increased risk of disturbances in embryonic development as a consequence. Further, the lack of any difference between wild and cultured females in terms of their egg DHA content indicates that there is a strong genetic influence on levels of this fatty acid in salmon eggs.

Genetic organization of the mouse t complex

The mouse t complex (also known as the T locus or T/t complex) is a large region of chromosome 17 that has intrigued geneticists for more than 50 years with its striking and unorthodox features. These include suppression of recombination, disturbances of embryonic development and alterations of sperm differentiation and function. Much of our knowledge concerning the properties of this genetic complex is based on the early work performed by S. Gluecksohn Waelsch and L. C. Dunn with mutant forms of the t complex called t haplotypes (previously known as t alleles or t mutations). Many t haplotypes are characterized by lethal actions at particular stages during early embryogenesis. Lethal t haplotypes can be placed into a number of groups where members of each group do not complement each other. Complementation between t haplotypes of different groups is not complete, and prenatal death occurs in many, but not all, doubly heterozygous (V/t”) embryos. Furthermore, all males doubly heterozygous for two lethal haplotypes are completely sterile. Other genes defined separately from t haplotypes but mapping within the t complex include Brachyury (T), Kinky (Fuk’) and Knobbly (Fukb), which are recessive embryonic lethals; Hybrid sterility-l (Hst-7) and Quaking (qk), which cause male-specific sterility; Hye, which affects the level of male-specific H-Y antigen expression; and Gtl, which determines acceptance or rejection specifically of embryonal carcinoma cell grafts. All observations to date imply a crucial role for the t complex in mechanisms of development and differentiation. At the present time, however, the molecular events responsible for these t complex effects remain elusive. This review will therefore focus on recent advances in our understanding of the structure, rather than the function, of this region. All known t haplotypes originated from wild populations, and almost all wild mouse populations analyzed from around the world have been found to be polymorphic for lethal or semi-lethal t haplotypes. Maintenance of a deleterious gene in a wild population is unexpected, but can be accounted for in this case by a further property of t haplotypes called transmission-ratio distortion (also known as segregation distortion). A wild heterozygous (+/t) male can transmit his t haplotype to more than 95% of his offspring, and it appears that the advantage of the t haplotype at fertilization can overcome the disadvantage of a certain frequency of homozygous lethality in the population as a whole. Genetic systems that involve the maintenance of deleterious gene complexes in wild populations by transmission-ratio distortion have been identified in other well studied species, and include the SD complex of Drosophila melanogaster, and the Spore Killer (SK) complex in Neurospora (Turner and Minireviews

Investigations in relation to teratological population statistics and the ethiology of disturbances of embryonic development in cattle. I. Teratological Population Statistics

Investigations in relation to teratological population statistics and the ethiology of disturbances of embryonic development in cattle. I. Teratological Population Statistics

Disturbance of embryonic development by maternal vitamin deficiencies.

Disturbance of embryonic development by maternal vitamin deficiencies.