WDR81 mutations cause extreme microcephaly and impair mitotic progression in human fibroblasts and Drosophila neural stem cells.

Microlissencephaly is a rare brain malformation characterized by congenital microcephaly and lissencephaly. Microlissencephaly is suspected to result from abnormalities in the proliferation or survival of neural progenitors. Despite the recent identification of six genes involved in microlissencephaly, the pathophysiological basis of this condition remains poorly understood. We performed trio-based whole exome sequencing in seven subjects from five non-consanguineous families who presented with either microcephaly or microlissencephaly. This led to the identification of compound heterozygous mutations in WDR81, a gene previously associated with cerebellar ataxia, intellectual disability and quadrupedal locomotion. Patient phenotypes ranged from severe microcephaly with extremely reduced gyration with pontocerebellar hypoplasia to moderate microcephaly with cerebellar atrophy. In patient fibroblast cells, WDR81 mutations were associated with increased mitotic index and delayed prometaphase/metaphase transition. Similarly, in vivo, we showed that knockdown of the WDR81 orthologue in Drosophila led to increased mitotic index of neural stem cells with delayed mitotic progression. In summary, we highlight the broad phenotypic spectrum of WDR81-related brain malformations, which include microcephaly with moderate to extremely reduced gyration and cerebellar anomalies. Our results suggest that WDR81 might have a role in mitosis that is conserved between Drosophila and humans.

[Migrant health and ethical requirements]. / Santé des migrants et exigence éthique.

Migrants' health is a subject that is often called up for aspects that are often presented as negative (insecurity, carelessness of public finances, major cultural replacement) in the name of which suspicion and rejection take hold. This vision does not survive the factual analysis of public health, social and economic data. Nevertheless, National Consultative Ethics Committee in its opinion 127 in 2017 draws up a serious, and still topical, assessment of the situation with regard to the health of migrants. In it, he denounced the use of migrant health care as an instrument for political purposes and advocated hospitality and fraternity.

In utero ultrasound diagnosis of corpus callosum agenesis leading to the identification of orofaciodigital type 1 syndrome in female fetuses.

BACKGROUND: OFD1 syndrome is a rare ciliopathy inherited on a dominant X-linked mode, typically lethal in males in the first or second trimester of pregnancy. It is characterized by oral cavity and digital anomalies possibly associated with cerebral and renal signs. Its prevalence is between 1/250,000 and 1/50,000 births. It is due to heterozygous mutations of OFD1 and mutations are often de novo (75%). Familial forms show highly variable phenotypic expression. OFD1 encodes a protein involved in centriole growth, distal appendix formation, and ciliogenesis. CASES: We report the investigation of three female fetuses in which corpus callosum agenesis was detected by ultrasound during the second trimester of pregnancy. In all three fetuses, fetopathological examination allowed the diagnosis of OFD1 syndrome, which was confirmed by molecular analysis. CONCLUSIONS: To our knowledge, these are the first case reports of antenatal diagnosis of OFD1 syndrome in the absence of familial history, revealed following detection of agenesis of the corpus callosum. They highlight the impact of fetal examination following termination of pregnancy for brain malformations. They also highlight the contribution of ciliary genes to corpus callosum development.