Molecular analysis of holoprosencephaly in South America

New SHH and Known SIX3 Variants in a Series of Latin American Patients with Holoprosencephaly

Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the SHH, SIX3, ZIC2, and TGIF1 genes explain ∼25% of the known causes of nonchromosomal HPE. We studied these 4 genes and clinically described 27 Latin American families presenting with nonchromosomal HPE. Three new SHH variants and a third known SIX3 likely pathogenic variant found by Sanger sequencing explained 15% of our cases. Genotype-phenotype correlation in these 4 families and published families with identical or similar driver gene, mutated domain, conservation of residue in other species, and the type of variant explain the pathogenicity but not the phenotypic variability. Nine patients, including 2 with SHH pathogenic variants, presented benign variants of the SHH, SIX3, ZIC2, and TGIF1 genes with potential alteration of splicing, a causal proposition in need of further studies. Finding more families with the same SIX3 variant may allow further identification of genetic or environmental modifiers explaining its variable phenotypic expression.

An mRNA characterization model predicting survival in patients with invasive breast cancer based on The Cancer Genome Atlas database

BACKGROUND

Invasive breast cancer is a highly heterogeneous tumor, although there have been many prediction methods for invasive breast cancer risk prediction, the prediction effect is not satisfactory. There is an urgent need to develop a more accurate method to predict the prognosis of patients with invasive breast cancer.

OBJECTIVE

To identify potential mRNAs and construct risk prediction models for invasive breast cancer based on bioinformaticsMETHODS: In this study, we investigated the differences in mRNA expression profiles between invasive breast cancer and normal breast samples, and constructed a risk model for the prediction of prognosis of invasive breast cancer with univariate and multivariate Cox analyses.

RESULTS

We constructed a risk model comprising 8 mRNAs (PAX7, ZIC2, APOA5, TP53AIP1,MYBPH, USP41, DACT2, and POU3F2) for the prediction of invasive breast cancer prognosis. We used the 8-mRNA risk prediction model to divide 1076 samples into high-risk groups and low-risk groups, the Kaplan-Meier curve showed that the high-risk group was closely related to the poor prognosis of overall survival in patients with invasive breast cancer. The receiver operating characteristic curve revealed an area under the curve of 0.773 for the 8 mRNA model at 3-year overall survival, indicating that this model showed good specificity and sensitivity for prediction of prognosis of invasive breast cancer.

CONCLUSIONS

The study provides an effective bioinformatic analysis for the better understanding of the molecular pathogenesis and prognosis risk assessment of invasive breast cancer.

The role of teratogens in neural crest development

The neural crest (NC), discovered by Wilhelm His 150 years ago, gives rise to a multipotent migratory embryonic cell population that generates a remarkably diverse and important array of cell types during the development of the vertebrate embryo. These cells originate in the neural plate border (NPB), which is the ectoderm between the neural plate and the epidermis. They give rise to the neurons and glia of the peripheral nervous system, melanocytes, chondrocytes, smooth muscle cells, odontoblasts and neuroendocrine cells, among others. Neurocristopathies are a class of congenital diseases resulting from the abnormal induction, specification, migration, differentiation or death of NC cells (NCCs) during embryonic development and have an important medical and societal impact. In general, congenital defects affect an appreciable percentage of newborns worldwide. Some of these defects are caused by teratogens, which are agents that negatively impact the formation of tissues and organs during development. In this review, we will discuss the teratogens linked to the development of many birth defects, with a strong focus on those that specifically affect the development of the NC, thereby producing neurocristopathies. Although increasing attention is being paid to the effect of teratogens on embryonic development in general, there is a strong need to critically evaluate the specific role of these agents in NC development. Therefore, increased understanding of the role of these factors in NC development will contribute to the planning of strategies aimed at the prevention and treatment of human neurocristopathies, whose etiology was previously not considered.

Premaxilla: up to which age it remains separated from the maxilla by a suture, how often it occurs in children and adults, and possible clinical and therapeutic implications: Study of 1,138 human skulls

Objective:

To evaluate topographic and temporal aspects of premaxillary bone and premaxillary-maxillary suture, since they are fundamental anatomical elements little explored clinically.

Methods:

1,138 human dry skulls were evaluated, of which 116 (10.19%) of the specimens were children, and 1,022 (89.81%) were adults. The skulls were photographed and the percentage of premaxillary-maxillary suture opening was determined. Subsequently the data were tabulated and submitted to statistical analysis, adopting a level of significance of 5%.

Results:

The progression of premaxillary suture closure from birth to 12 years of age was 3.72% per year. In 100% of the skulls up to 12 years, the premaxillary-maxillary suture open in the palatal region was observed, while 6.16% of adults presented different degrees of opening.

Conclusions:

The premaxilla exists in an independent way within the maxillary complex and the presence of the premaxilla-maxillary suture justifies the success of anteroposterior expansions to stimulate the growth of the middle third of the face, solving anatomical and functional problems.

External and computed tomography analysis of a strophocephalic lamb

CONTEXT

The Museum of Anatomy and Embryology Louis Deroubaix attached to the Laboratory of Anatomy, Biomecanics and Organogenesis, ULB, Brussels, possesses in its liquid collections a cephalic extremity of a lamb suffering from strophocephaly. The origins have not been determined. The trunk and the limbs are resected.

MATERIAL AND METHODS

The piece has been studied and photographed. A volumic computed tomography acquisition has been performed with a Siemens Volume Zoom. For pedagogic and museological purposes, surface reconstructions and 3D printing have been obtained.

RESULTS

An otocephaly is observed. Both ears are located in place of the oral cavity. The mandible is welded to the braincase. The eyeballs are close together (synophtalmia) which confirms the presence of a cyclotocephaly. They are surmounted by a rudimentary snout rather than a proboscis. The presence of this muzzle allows the anomaly to be classified as a strophocephaly, a malformation already described in sheeps. CT slices of the brain show a semi-lobar holoprosencephaly with incomplete division of the cerebral hemispheres and ventricules.

DISCUSSION AND CONCLUSION

The CT examination allows the facial anomalies to be allocated to a holoprosencephaly. The singularity of this case, compared to the human cyclotocephalies, is the presence of a differentiated muzzle rather than a simple proboscis. The holoprosencephaly is uncomplete. Such anomalies have been associated with an entire absence of cerebral differentiation but with a complete absence of the muzzle. The tridimensional printing represents an interesting educational tool easily transportable in contrast to the original specimen.

[Morphologic and tomodensitometric comparative analysis of two cyclotocephalic newborns]

Two specimens of cyclotocephalic newborns, coming from museum collections, have been the subject of a comparative morphologic analysis. This one comprised an external examination and a CT scan exploration. If the craniofacial features were similar, one had a quasi-normal brain, while the second specimen displayed alobar holoprosencephaly. This observation relatively surprising is discussed in the light of current knowledge on the developmental genetics of this family of malformations.