KIAA0586, the human ortholog of chicken TALPID3, is a centrosomal protein that is essential for primary ciliogenesis. Its disruption in animal models causes defects attributed to abnormal hedgehog ...signaling; these defects include polydactyly and abnormal dorsoventral patterning of the neural tube. Here, we report homozygous mutations of KIAA0586 in four families affected by lethal ciliopathies ranging from a hydrolethalus phenotype to short-rib polydactyly. We show defective ciliogenesis, as well as abnormal response to SHH-signaling activation in cells derived from affected individuals, consistent with a role of KIAA0586 in primary cilia biogenesis. Whereas centriolar maturation seemed unaffected in mutant cells, we observed an abnormal extended pattern of CEP290, a centriolar satellite protein previously associated with ciliopathies. Our data show the crucial role of KIAA0586 in human primary ciliogenesis and subsequent abnormal hedgehog signaling through abnormal GLI3 processing. Our results thus establish that KIAA0586 mutations cause lethal ciliopathies.
Bothnian palmoplantar keratoderma (PPKB, MIM600231) is an autosomal dominant form of diffuse non-epidermolytic PPK characterized by spontaneous yellowish-white PPK associated with a spongy appearance ...after water-immersion. It is due to
heterozygous mutations. We report four patients carrying a novel
heterozygous mutation (c.125T>A; p.(Ile42Asn)), and belonging to the same French family. Early palmoplantar swelling (before one year of age), pruritus and hyperhidrosis were constant. The PPK was finally characterized as transgrediens, non-progrediens, diffuse PPK with a clear delineation between normal and affected skin. The cutaneous modifications at water-immersion test, "hand-in-the-bucket sign", were significantly evident after 3 to 6 min of immersion in the children and father, respectively. AQP5 protein is expressed in eccrine sweat glands (ESG), salivary and airway submucosal glands. In PPKB, gain of function mutations seem to widen the channel diameter of ESG and increase water movement. Thus, swelling seems to be induced by hypotonicity with water entrance into cells, while hyperhidrosis is the result of an increased cytosolic calcium concentration.
TALPID3/KIAA0586 is an evolutionary conserved protein, which plays an essential role in protein trafficking. Its role during gastrointestinal (GI) and enteric nervous system (ENS) development has not ...been studied previously. Here, we analyzed chicken, mouse and human embryonic GI tissues with TALPID3 mutations. The GI tract of TALPID3 chicken embryos was shortened and malformed. Histologically, the gut smooth muscle was mispatterned and enteric neural crest cells were scattered throughout the gut wall. Analysis of the Hedgehog pathway and gut extracellular matrix provided causative reasons for these defects. Interestingly, chicken intra-species grafting experiments and a conditional knockout mouse model showed that ENS formation did not require TALPID3, but was dependent on correct environmental cues. Surprisingly, the lack of TALPID3 in enteric neural crest cells (ENCC) affected smooth muscle and epithelial development in a non-cell-autonomous manner. Analysis of human gut fetal tissues with a
mutation showed strikingly similar findings compared to the animal models demonstrating conservation of TALPID3 and its necessary role in human GI tract development and patterning.
Centrioles are microtubule-based, barrel-shaped structures that initiate the assembly of centrosomes and cilia. How centriole length is precisely set remains elusive. The microcephaly protein CPAP ...(also known as MCPH6) promotes procentriole growth, whereas the oral-facial-digital (OFD) syndrome protein OFD1 represses centriole elongation. Here we uncover a new subtype of OFD with severe microcephaly and cerebral malformations and identify distinct mutations in two affected families in the evolutionarily conserved C2CD3 gene. Concordant with the clinical overlap, C2CD3 colocalizes with OFD1 at the distal end of centrioles, and C2CD3 physically associates with OFD1. However, whereas OFD1 deletion leads to centriole hyperelongation, loss of C2CD3 results in short centrioles without subdistal and distal appendages. Because C2CD3 overexpression triggers centriole hyperelongation and OFD1 antagonizes this activity, we propose that C2CD3 directly promotes centriole elongation and that OFD1 acts as a negative regulator of C2CD3. Our results identify regulation of centriole length as an emerging pathogenic mechanism in ciliopathies.
In P63‐related ectodermal dysplasias (ED), the clinical characteristics focus on extra‐cutaneous manifestations. The dermatological phenotype remains incompletely characterized. We report the ...dermatological features of 22 patients carrying a TP63 mutation. Erosions, erythroderma and pigmentary anomalies are characteristics of P63‐related ED. Our data suggest that patients might be classified into two major P63‐related disorders: AEC and EEC. RHS and ADULT represent mild AEC and EEC forms, respectively.
Fetal anemias are serious complications during pregnancies, which could lead to fetal death in case of hydrops fetalis (1/3000 pregnancies). Fetal anemia and hydrops fetalis are in most cases the ...result of fetal maternal alloimmunization, parvovirus B19 infection, fetal maternal hemorrhage, chromosomal abnormalities, congenital malformations, metabolic diseases, and in the context of hematological disorders, alpha-thalassemia. However, in one case out of 5, fetal anemia remains unexplained after an exhaustive first line of etiological evaluation. In order to identify the cause of the unexplained fetal anemia and to provide advice regarding prenatal diagnosis for next pregnancy, we have developed useful diagnostic tools on fetal blood based on erythrocyte and reticulocyte indices, examination of red cell morphology, flow cytometry (EMA test), osmotic gradient ektacytometry and molecular screening analysis.
43 fetal samples (30 probands) have been referred to our Hematology diagnostic lab in the time span between 2012-2018. In majority of the cases, various analyses were performed on fetal blood (23 out of 43) and in other instances during post-mortem examination following death (17 out of 43). Fetal blood purity was confirmed by microsatellite analysis on both parental and fetal DNAs. Informed consent was obtained from the mother in all cases. In 6 of 43 cases, prenatal diagnosis was performed after identification of the causal mutation responsible for the hydrops fetalis in the first fetus. Hydrops fetalis was suspected in 24 cases at the time of fetal sample collection. Red cell morphology and ektacytometry enabled the establishment of clinical diagnostic in two cases (congenital dyserythropoiesis type II (CDAII) and xerocytosis). Molecular screening analysis was performed by Sanger sequencing technique from 2012 to July 2016 and subsequently we designed a targeted Next Generation Sequencing (NGS) library including 74 genes involved in red cell disorders (n=9 fetuses) and exome sequencing (WES) was performed for 4 fetuses. Each identified allelic variation was confirmed by Sanger sequencing technique. Molecular Biology analysis (except the 6 prenatal diagnosis cases) was performed on 21 of 37 fetuses that enabled identification of the molecular defect in 10 fetuses. Rare red cell disorders were diagnosed in these cases including Diamond-Blackfan anemia (n=2), congenital dyserythropoiesis (n=6) and stomatocytosis (n=2) respectively. No putative pathogenous allelic variation following molecular screening could be identified in 4 fetuses. In the 6 cases which were screened for the molecular defect previously identified, none of the tested fetuses exhibited the allelic variation identified in the first fetus.
In summary, targeted-NGS and WES are very valuable tools in the causal diagnosis of hydrops fetalis dues to unexplained anemia in addition to routine hematological tests (erythrocyte and reticulocyte indices, red cell morphology, flow cytometry, and ektacytometry) and after elimination of the most frequent causes of hydrops fetalis. This clinical problem is more frequent than has been previously surmised and needs more attention.
No relevant conflicts of interest to declare.
TCTN3 Mutations Cause Mohr-Majewski Syndrome Thomas, Sophie; Legendre, Marine; Saunier, Sophie ...
American journal of human genetics,
08/2012, Letnik:
91, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Orofaciodigital syndromes (OFDSs) consist of a group of heterogeneous disorders characterized by abnormalities in the oral cavity, face, and digits and associated phenotypic abnormalities that lead ...to the delineation of 13 OFDS subtypes. Here, by a combined approach of homozygozity mapping and exome ciliary sequencing, we identified truncating TCTN3 mutations as the cause of an extreme form of OFD associated with bone dysplasia, tibial defect, cystic kidneys, and brain anomalies (OFD IV, Mohr-Majewski syndrome). Analysis of 184 individuals with various ciliopathies (OFD, Meckel, Joubert, and short rib polydactyly syndromes) led us to identify four additional truncating TCTN3 mutations in unrelated fetal cases with overlapping Meckel and OFD IV syndromes and one homozygous missense mutation in a family with Joubert syndrome. By exploring roles of TCTN3 in human ciliary related functions, we found that TCTN3 is necessary for transduction of the sonic hedgehog (SHH) signaling pathway, as revealed by abnormal processing of GLI3 in patient cells. These results are consistent with the suggested role of its murine ortholog, which forms a complex at the ciliary transition zone with TCTN1 and TCTN2, both of which are also implicated in the transduction of SHH signaling. Overall, our data show the involvement of the transition zone protein TCTN3 in the regulation of the key SHH signaling pathway and that its disruption causes a severe form of ciliopathy, combining features of Meckel and OFD IV syndromes.
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