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International audience; Congenital anomalies of the kidney and urinary tract (CAKUT) constitute a major cause of chronic kidney disease in children and 20% of prenatally detected anomalies. CAKUT encompass a spectrum of developmental kidney defects, including renal agenesis, hypoplasia, and cystic and non-cystic dysplasia. More than 50 genes have been reported as mutated in CAKUT-affected case subjects. However, the pathophysiological mechanisms leading to bilateral kidney agenesis (BKA) remain largely elusive. Whole-exome or targeted exome sequencing of 183 unrelated familial and/or severe CAKUT-affected case subjects, including 54 fetuses with BKA, led to the identification of 16 heterozygous variants in GREB1L (growth regulation by estrogen in breast cancer 1-like), a gene reported as a target of retinoic acid signaling. Four loss-of-function and 12 damaging missense variants, 14 being absent from GnomAD, were identified. Twelve of them were present in familial or simplex BKA-affected case subjects. Female BKA-affected fetuses also displayed uterus agenesis. We demonstrated a significant association between GREB1L variants and BKA. By in situ hybridization, we showed expression of Greb1l in the nephrogenic zone in developing mouse kidney. We generated a Greb1l knock-out mouse model by CRISPR-Cas9. Analysis at E13.5 revealed lack of kidneys and genital tract anomalies in male and female Greb1l-/- embryos and a slight decrease in ureteric bud branching in Greb1l+/- embryos. We showed that Greb1l invalidation in mIMCD3 cells affected tubulomorphogenesis in 3D-collagen culture, a phenotype rescued by expression of the wild-type human protein. This demonstrates that GREB1L plays a major role in early metanephros and genital development in mice and humans.

Coene, Karlien/0000-0001-9873-1458; Alanay, Yasemin/0000-0003-0683-9731; THOMAS, Sophie/0000-0002-8569-3277; Lyonnet, Stanislas/0000-0001-5426-9417; Akarsu, Nurten/0000-0001-5432-0032; ATTIE-BITACH, Tania/0000-0002-1155-3626; Davis, Erica/0000-0002-2412-8397; Boduroglu, Koray/0000-0001-6260-1942; Cagnard, Nicolas/0000-0002-9051-1896; cormier-daire, valerie/0000-0002-2839-9856; Katsanis, Nicholas/0000-0002-2480-0171; PUTOUX, Audrey/0000-0001-5496-4604 WOS: 000291017000021 PubMed: 21552264 KIF7, the human ortholog of Drosophila Costal2, is a key component of the Hedgehog signaling pathway. Here we report mutations in KIF7 in individuals with hydrolethalus and acrocallosal syndromes, two multiple malformation disorders with overlapping features that include polydactyly, brain abnormalities and cleft palate. Consistent with a role of KIF7 in Hedgehog signaling, we show deregulation of most GLI transcription factor targets and impaired GLI3 processing in tissues from individuals with KIF7 mutations. KIF7 is also a likely contributor of alleles across the ciliopathy spectrum, as sequencing of a diverse cohort identified several missense mutations detrimental to protein function. In addition, in vivo genetic interaction studies indicated that knockdown of KIF7 could exacerbate the phenotype induced by knockdown of other ciliopathy transcripts. Our data show the role of KIF7 in human primary cilia, especially in the Hedgehog pathway through the regulation of GLI targets, and expand the clinical spectrum of ciliopathies. ANRFrench National Research Agency (ANR) [07-MRAR-010-02, BLAN-1122-01]; E-RARE [07-ERare-001-01]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108S420]; US National Institutes of Health from the National Institute of Child Health and Development [R01HD04260]; National Institute of Diabetes, Digestive and Kidney DisordersUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK) [R01DK072301]; Academie de Medecine; NIHUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [NS039818-07]; Huygens Scholarship Programme; Netherlands Organization for Scientific ResearchNetherlands Organization for Scientific Research (NWO) [NWO Toptalent-021.001.014]; March of Dimes FoundationMarch of Dimes [1-FY07-422]; Medical Research CouncilMedical Research Council UK (MRC) [G0801843] We are grateful to families and to the French Society of Fetal Pathology (SOFFOET) for participating in the study, to C. Dubourg, P. Wieacker, B. Leroy, N. Laurent, V. Fermeaux, S. Odent for fetuses' referral and to A. Schinzel and A. David for ACLS samples. We thank M. Zarhrate, A. Aguilar, N. Spasky and L. Besse for technical help. We thank N. Boddaert for helpful discussion. This work was supported by grants from ANR (FETALCILIOPATHIES number 07-MRAR-010-02 and FOETOCILPATH number BLAN-1122-01), E-RARE (Cranirare number 07-ERare-001-01) the Scientific and Technological Research Council of Turkey (TUBITAK, grant number 108S420 to N. A. A.), the US National Institutes of Health grant R01HD04260 from the National Institute of Child Health and Development (N. K.), R01DK072301 from the National Institute of Diabetes, Digestive and Kidney Disorders (N. K.) and the European Union (EU-SYSCILIA; E. E. D., N. K. and P. L. B.). A. P. was granted a fellowship from the Academie de Medecine. S. T. is supported by NIH 'Hereditary Basis of Neural Tube Defects' No NS039818-07 to M. Speer. K. L. M. C. is supported by the Huygens Scholarship Programme and the Netherlands Organization for Scientific Research (NWO Toptalent-021.001.014). M. W. was a fellow of the Guggenheim Foundation and was supported by the March of Dimes Foundation (1-FY07-422). P. L. B. is a Wellcome Trust Senior Research Fellow. N. K. is a Distinguished George W. Brumley Professor.

We report on four patients from three families, with similar radiological findings: absent (or severely delayed) ossification of vertebral bodies and associated anomalies. The babies were stillborn or died soon after birth of respiratory insufficiency. Two patients are sibs (female and male) born to first cousin Malian parents. The two others were non-consanguineous. This perinatally lethal entity comprises short neck, short wide thorax, and normally shaped limbs. Associated, inconstant anomalies are myelomeningocele, cystic kidneys with nephrogenic rests (in the sibs), and cleft palate. Radiologically, the hallmarks are absence of ossification of the vertebral bodies and sacrum, abnormal position of the vertebral pedicles, which are lamellar and angulated, ribbon-like ribs reduced in number, narrow pelvis, upward widening of the iliac wings, and unusual tilt of the ischiopubic rami, contrasting with the normal appendicular skeleton. Maroteaux briefly described one of the patients in the 2002 edition of "Maladies osseuses de l'enfant" and three sibs with similar renal and radiological findings were reported in 2003 in this Journal. Combined with the latter cases, these four new patients allow delineation of a specific lethal AR syndrome with ossification defect of the axial skeleton and renal dysplasia. We propose to name this entity diaphanospondylodysostosis.