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Background: Fontaine progeroid syndrome (FPS, OMIM 612289) is a recently identified genetic disorder stemming from pathogenic variants in the SLC25A24 gene, encoding a mitochondrial carrier protein. It encompasses Gorlin–Chaudry–Moss syndrome and Fontaine–Farriaux syndrome, primarily manifesting as craniosynostosis with brachycephaly, distinctive dysmorphic facial features, hypertrichosis, severe prenatal and postnatal growth restriction, limb shortening, and early aging with characteristic skin changes, phalangeal anomalies, and genital malformations. Cases: All known occurrences of FPS have been postnatally observed until now. Here, we present the first two prenatal cases identified during the second trimester of pregnancy. While affirming the presence of most postnatal abnormalities in prenatal cases, we note the absence of a progeroid appearance in young fetuses. Notably, our reports introduce new phenotypic features like encephalocele and nephromegaly, which were previously unseen postnatally. Moreover, paternal SLC25A24 mosaicism was detected in one case. Conclusions: We present the initial two fetal instances of FPS, complemented by thorough phenotypic and genetic assessments. Our findings expand the phenotypical spectrum of FPS, unveiling new fetal phenotypic characteristics. Furthermore, one case underscores a potential novel inheritance pattern in this disorder. Lastly, our observations emphasize the efficacy of exome/genome sequencing in both prenatal and postmortem diagnosis of rare polymalformative syndromes with a normal karyotype and array‐based comparative genomic hybridization (CGH). [ABSTRACT FROM AUTHOR]

Introduction: CREBBP truncating mutations and deletions are responsible for the well‐known Rubinstein‐Taybi syndrome. Recently, a new, distinct CREBBP‐linked syndrome has been described: missense mutations located at the 3′ end of exon 30 and the 5′ portion of exon 31 induce Menke‐Hennekam syndrome. Patients with this syndrome present a recognizable facial dysmorphism, intellectual disability of variable severity, microcephaly, short stature, autism, epilepsy, visual and hearing impairments, feeding problems, upper airway infections, scoliosis, and/or kyphosis. To date, all diagnoses were made postnatally. Method and Case Report: Trio‐whole exome sequencing (WES) was performed in a fetus showing increased nuchal translucency persistence and aorta abnormalities at 28 weeks of gestation (WG). Results: WES revealed a CREBBP de novo missense mutation (c.5602C>T; p.Arg1868Trp) in exon 31, previously reported as the cause of Menke‐Hennekam syndrome. Termination of pregnancy was performed at 32 WG. We further reviewed the prenatal signs of Menke‐Hennekam syndrome already reported. Among the 35 patients reported and diagnosed postnatally up to this day, 15 presented recognizable prenatal signs, the most frequent being intra‐uterine growth retardation, brain, and cardiovascular anomalies. Conclusion: Menke‐Hennekam is a rare syndrome with unspecific, heterogeneous, and inconstant prenatal symptoms occurring most frequently with the c.5602C>T, p.(Arg1868Trp) mutation. Therefore, the prenatal diagnosis of Menke‐Hennekam syndrome is only possible by molecular investigation. Moreover, this case report and review reinforce the importance of performing prenatal WES when unspecific signs are present on imaging. [ABSTRACT FROM AUTHOR]

Background and objective: Poly(A)‐specific ribonuclease (PARN) mutations have been associated with familial pulmonary fibrosis. This study aims to describe the phenotype of patients with interstitial lung disease (ILD) and heterozygous PARN mutations. Methods: We performed a retrospective, observational, non‐interventional study of patients with an ILD diagnosis and a pathogenic heterozygous PARN mutation followed up in a centre of the OrphaLung network. Results: We included 31 patients (29 from 16 kindreds and two sporadic patients). The median age at ILD diagnosis was 59 years (range 54 to 63). In total, 23 (74%) patients had a smoking history and/or fibrogenic exposure. The pulmonary phenotypes were heterogenous, but the most frequent diagnosis was idiopathic pulmonary fibrosis (n = 12, 39%). Haematological abnormalities were identified in three patients and liver disease in two. In total, 21 patients received a specific treatment for ILD: steroids (n = 13), antifibrotic agents (n = 11), immunosuppressants (n = 5) and N‐acetyl cysteine (n = 2). The median forced vital capacity decline for the whole sample was 256 ml/year (range −363 to −148). After a median follow‐up of 32 months (range 18 to 66), 10 patients had died and six had undergone lung transplantation. The median transplantation‐free survival was 54 months (95% CI 29 to ∞). Extra‐pulmonary features were less frequent with PARN mutation than telomerase reverse transcriptase (TERT) or telomerase RNA component (TERC) mutation. Conclusion: IPF is common among individuals with PARN mutation, but other ILD subtypes may be observed. The pulmonary phenotypes of 31 patients with interstitial lung disease (ILD) and heterozygous poly(A)‐specific ribonuclease (PARN) mutations in this cohort were heterogeneous, but idiopathic pulmonary fibrosis was the most frequent diagnosis. Haematological and hepatic features were less frequent than in patients affected with telomerase reverse transcriptase (TERT)‐ or telomerase RNA component (TERC)‐associated ILDs. [ABSTRACT FROM AUTHOR]

Objective: To elucidate the molecular cause in a well-characterized cohort of patients with Congenital Hypothyroidism (CH) and Dyshormonogenesis (DH) by using targeted next-generation sequencing (TNGS). Study design: We studied 19 well-characterized patients diagnosed with CH and DH by targeted NGS including genes involved in thyroid hormone production. The pathogenicity of novel mutations was assessed based on in silico prediction tool results, functional studies when possible, variant location in important protein domains, and a review of the recent literature. Results: TNGS with variant prioritization and detailed assessment identified likely disease-causing mutations in 10 patients (53%). Monogenic defects most often involved TG , followed by DUOXA2 , DUOX2 , and NIS and were usually homozygous or compound heterozygous. Our review shows the importance of the detailed phenotypic description of patients and accurate analysis of variants to provide a molecular diagnosis. Conclusions: In a clinically well-characterized cohort, TNGS had a diagnostic yield of 53%, in accordance with previous studies using a similar strategy. TG mutations were the most common genetic defect. TNGS identified gene mutations causing DH, thereby providing a rapid and cost-effective genetic diagnosis in patients with CH due to DH. [ABSTRACT FROM AUTHOR]

Background Apolipoprotein L1 (APOL1) risk variants are strongly associated with sporadic focal segmental glomerulosclerosis (FSGS) in populations with African ancestry. We determined the frequency of G1/G2 variants in steroid-resistant nephrotic syndrome (SRNS)/FSGS patients with African or French West Indies ancestry in France and its relationships with other SRNS genes. Methods In a cohort of 152 patients (139 families), the APOL1 risk variants were genotyped by direct Sanger sequencing and pathogenic mutations were screened by next-generation sequencing with a panel including 35 SRNS genes. Results The two risk allele [high-risk (HR)] genotypes were found in 43.1% (66/152) of subjects compared with 18.9% (106/562) in a control population (P < 0.0001): 33 patients homozygous for APOL1 G1 alleles, 4 homozygous for G2 and 29 compound heterozygous for G1 and G2. Compared with patients in the low-risk (LR) group, patients in the HR group were more likely to originate from the French West Indies than from Africa [45/66 (68.2%) versus 30/86 (34.9%); P < 0.0001]. There were more familial cases in the HR group [27 (41.5%) versus 8 (11.4%); P < 0.0001]. However, causative mutations in monogenic SRNS genes were found in only 1 patient in the HR group compared with 16 patients (14 families) in the LR group (P = 0.0006). At diagnosis, patients in the HR group without other mutations were more often adults [35 (53.8%) versus 19 (27.1%); P = 0.003] and had a lower estimated glomerular filtration rate (78.9 versus 98.8 mL/min/1.73 m2; P = 0.02). Conclusions The HR genotype is frequent in FSGS patients with African ancestry in our cohort, especially in those originating from the West Indies, and confer a poor renal prognosis. It is usually not associated with other causative mutations in monogenic SRNS genes. [ABSTRACT FROM AUTHOR]

Background and Aims An expanding number of monogenic defects have been identified as causative of severe forms of very early-onset inflammatory bowel diseases [VEO-IBD]. The present study aimed at defining how next-generation sequencing [NGS] methods can be used to improve identification of known molecular diagnosis and to adapt treatment. Methods A total of 207 children were recruited in 45 paediatric centres through an international collaborative network [ESPGHAN GENIUS working group] with a clinical presentation of severe VEO-IBD [ n = 185] or an anamnesis suggestive of a monogenic disorder [ n = 22]. Patients were divided at inclusion into three phenotypic subsets: predominantly small bowel inflammation, colitis with perianal lesions, and colitis only. Methods to obtain molecular diagnosis included functional tests followed by specific Sanger sequencing, custom-made targeted NGS, and in selected cases whole exome sequencing [WES] of parents-child trios. Genetic findings were validated clinically and/or functionally. Results Molecular diagnosis was achieved in 66/207 children [32%]: 61% with small bowel inflammation, 39% with colitis and perianal lesions, and 18% with colitis only. Targeted NGS pinpointed gene mutations causative of atypical presentations, and identified large exonic copy number variations previously missed by WES. Conclusions Our results lead us to propose an optimised diagnostic strategy to identify known monogenic causes of severe IBD. [ABSTRACT FROM AUTHOR]

Background While mitochondrial DNA (mtDNA) copy number is strictly regulated during differentiation and according to cell type, very little is known regarding the mechanism which accurately controls mtDNA copy number in human. Exon 2 of the human POLG gene, encoding the catalytic subunit of the mitochondrialspecific DNA polymerase gamma, contains a CpG island, highly conserved in mice and human. Changes of DNA methylation at the POLG locus have been shown to modulate mtDNA copy number during cell differentiation in both mouse and human. Methods We have investigated the epigenetic modification of the POLG gene, by assessing the methylation level of its exon 2 using deep-Next Generation Sequencing analysis of bisulfite-treated DNA. Analysis were performed on various tissues at either postnatal or prenatal stages, on samples from carriers of mtDNA mutations, patients carrying two loss-of-function POLG mutations and controls. Results Very high methylation levels at POLG exon 2 were found (94±3%) and no variation was observed according to either developmental stage or tissue of origin, except for sperm samples for which lower methylation levels were found (80%). This high level of methylation was neither correlated with the presence of mtDNA mutations (94±1% of methylated alleles), nor with biallelic POLG mutations (93%±2%), even in tissues where a mtDNA depletion had been observed. Conclusions This study suggests that, at variance with mouse and un/de-differentiated human cells, differentiated human cells control mtDNA levels irrespective of POLG methylation. The factors which actually control the mtDNA levels in such cell types remain to be identified. [ABSTRACT FROM AUTHOR]

The sarcoplasmic reticulum is a network of tubules and cisternae localized in close association with the contractile apparatus, and regulates Ca2+ dynamics within striated muscle cell. The sarcoplasmic reticulum maintains its shape and organization despite repeated muscle cell contractions, through mechanisms which are still under investigation. The ESCRT complexes are essential to organize membrane subdomains and modify membrane topology in multiple cellular processes. Here, we report for the first time that ESCRT-II proteins play a role in the maintenance of sarcoplasmic reticulum integrity in C. elegans. ESCRT-II proteins colocalize with the sarcoplasmic reticulum marker ryanodine receptor UNC-68. The localization at the sarcoplasmic reticulum of ESCRT-II and UNC-68 are mutually dependent. Furthermore, the characterization of ESCRT-II mutants revealed a fragmentation of the sarcoplasmic reticulum network, associated with an alteration of Ca2+ dynamics. Our data provide evidence that ESCRT-II proteins are involved in sarcoplasmic reticulum shaping. [ABSTRACT FROM AUTHOR]

As a consequence one could hypothesize that the I CDK10 i gene is also a candidate gene for midline defects of the HPE spectrum including corpus callosum agenesis and SMMCI. Associations of a corpus callosum agenesis with a SMMCI syndrome and/or microform of holoprosencephaly are observed.4 The patient described in the present report carries a microform of holoprosencephaly. Direct silencing of CDK10 in cell lines results in longer cilia and alters the expression of a number of genes involved during ciliogenesis such as I BBS4 i , I CEP290 i , and I RPGRIP1l i .2 Pathogenic variations of these genes cause Bardet-Biedl, Joubert, and Meckel syndrome. [Extracted from the article]

Poc1 (Protein of Centriole 1) proteins are highly conserved WD40 domain-containing centriole components, well characterized in the alga Chlamydomonas, the ciliated protazoan Tetrahymena, the insect Drosophila and in vertebrate cells including Xenopus and zebrafish embryos. Functions and localizations related to the centriole and ciliary axoneme have been demonstrated for Poc1 in a range of species. The vertebrate Poc1 protein has also been reported to show an additional association with mitochondria, including enrichment in the specialized "germ plasm" region of Xenopus oocytes. We have identified and characterized a highly conserved Poc1 protein in the cnidarian Clytia hemisphaerica. Clytia Poc1 mRNA was found to be strongly expressed in eggs and early embryos, showing a punctate perinuclear localization in young oocytes. Fluorescence-tagged Poc1 proteins expressed in developing embryos showed strong localization to centrioles, including basal bodies. Anti-human Poc1 antibodies decorated mitochondria in Clytia, as reported in human cells, but failed to recognise endogenous or fluorescent-tagged Clytia Poc1. Injection of specific morpholino oligonucleotides into Clytia eggs prior to fertilization to repress Poc1 mRNA translation interfered with cell division from the blastula stage, likely corresponding to when neosynthesis normally takes over from maternally supplied protein. Cell cycle lengthening and arrest were observed, phenotypes consistent with an impaired centriolar biogenesis or function. The specificity of the defects could be demonstrated by injection of synthetic Poc1 mRNA, which restored normal development. We conclude that in Clytia embryos, Poc1 has an essentially centriolar localization and function. [ABSTRACT FROM AUTHOR]

Leber congenital amaurosis (LCA) encompasses the earliest and most severe retinal dystrophies and can occur as a non-syndromic or a syndromic disease. Molecular diagnosis in LCA is of particular importance in clinical decision-making and patient care since it can provide ocular and extraocular prognostics and identify patients eligible to develop gene-specific therapies. Routine high-throughput molecular testing in LCA yields 70%–80% of genetic diagnosis. In this study, we aimed to investigate the non-coding regions of one non-syndromic LCA gene, RPGRIP1, in a series of six families displaying one single disease allele after a gene-panel screening of 722 LCA families which identified 26 biallelic RPGRIP1 families. Using trio-based high-throughput whole locus sequencing (WLS) for second disease alleles, we identified a founder deep intronic mutation (NM_020366.3:c.1468-128T>G) in 3/6 families. We employed Sanger sequencing to search for the pathologic variant in unresolved LCA cases (106/722) and identified three additional families (two homozygous and one compound heterozygous with the NM_020366.3:c.930+77A>G deep intronic change). This makes the c.1468-128T>G the most frequent RPGRIP1 disease allele (8/60, 13%) in our cohort. Studying patient lymphoblasts, we show that the pathologic variant creates a donor splice-site and leads to the insertion of the pseudo-exon in the mRNA, which we were able to hamper using splice-switching antisense oligonucleotides (AONs), paving the way to therapies. [ABSTRACT FROM AUTHOR]

The prognostic value of IL7-receptor pathway (IL7Rp) mutations in T-cell acute lymphoblastic leukemia (T-ALL) remains unclear. We performed a comprehensive study of 200 adult patients with T-ALL included in the GRAALL2003/2005 protocols to address the clinical significance of IL7Rp mutations. Next-generation sequencing of the IL7Rp (IL7R/JAK1/JAK3/STAT5B) revealed that IL7Rp mutations were frequent in adult T-ALL (28%) particularly in immature/early T-cell progenitor (ETP)-ALL. They were associated with mutations of NOTCH-pathway, PHF6, and PRC2 components but not with K/NRAS. IL7Rp mutated (IL7Rp mut ) T-ALL were slow-responders, with a high rate of M2/M3 day-8 marrow compared with IL7Rp non-mutated (IL7Rp WT ) T-ALL (p = 0.002) and minimal residual disease positivity at 6-weeks (MRD1) (p = 0.008) but no difference in MRD2 positivity at 12-weeks. Despite this, no adverse prognosis was evidenced when censored for allogeneic hematopoietic stem cell transplantation (HSCT). In time-dependent analysis, HSCT did not benefit IL7Rp mut patients whereas it was of marked benefit to IL7Rp WT cases. IL7Rp-mutations identify a subgroup of slow-responder T-ALLs which benefit from post-induction chemotherapy regimens but not from HSCT. Our data suggest that prior knowledge of the mutation status of IL7Rp may influence HSCT decision and help to guide therapy reduction.

Green fluorescent proteins (GFPs) and calcium-activated photoproteins of the aequorin/clytin family, now widely used as research tools, were originally isolated from the hydrozoan jellyfish Aequora victoria. It is known that bioluminescence resonance energy transfer (BRET) is possible between these proteins to generate flashes of green light, but the native function and significance of this phenomenon is unclear. Using the hydrozoan Clytia hemisphaerica, we characterized differential expression of three clytin and four GFP genes in distinct tissues at larva, medusa and polyp stages, corresponding to the major in vivo sites of bioluminescence (medusa tentacles and eggs) and fluorescence (these sites plus medusa manubrium, gonad and larval ectoderms). Potential physiological functions at these sites include UV protection of stem cells for fluorescence alone, and prey attraction and camouflaging counter-illumination for bioluminescence. Remarkably, the clytin2 and GFP2 proteins, co-expressed in eggs, show particularly efficient BRET and co-localize to mitochondria, owing to parallel acquisition by the two genes of mitochondrial targeting sequences during hydrozoan evolution. Overall, our results indicate that endogenous GFPs and photoproteins can play diverse roles even within one species and provide a striking and novel example of protein coevolution, which could have facilitated efficient or brighter BRET flashes through mitochondrial compartmentalization.