Search

Introduction: Counseling osteogenesis imperfecta (OI) pregnancies is challenging due to the wide range of onsets and clinical severities, from perinatal lethality to milder forms detected later in life. Methods: Thirty-eight individuals from 36 families were diagnosed with OI through prenatal ultrasonography and/or postmortem clinical and radiographic findings. Genetic analysis was conducted on 26 genes associated with OI in these subjects that emerged over the past 20 years; while some genes were examined progressively, all 26 genes were examined in the group where no pathogenic variations were detected. Results: Prenatal and postnatal observations both consistently showed short limbs in 97%, followed by bowing of the long bones in 89%. Among 32 evaluated cases, all exhibited cranial hypomineralization. Fractures were found in 29 (76%) cases, with multiple bones involved in 18 of them. Genetic associations were disclosed in 27 families with 22 (81%) autosomal dominant and five (19%) autosomal recessive forms, revealing 25 variants in six genes (COL1A1, COL1A2, CREB3L1, P3H1, FKBP10, and IFITM5), including nine novels. Postmortem radiological examination showed variability in intrafamily expression of CREBL3- and P3H1-related OI. Conclusion: Prenatal diagnosis for distinguishing OI and its subtypes relies on factors such as family history, timing, ultrasound, genetics, and postmortem evaluation. [ABSTRACT FROM AUTHOR]

Congenital hearing loss has an impact on almost every facet of life. In more than 50% of cases, a genetic cause can be identified. Currently, extensive genetic testing is available, although the etiology of some patients with obvious familial hearing loss remains unknown. We selected a cohort of mutation-negative patients to optimize the diagnostic yield for genetic hearing impairment. In this retrospective study, 21 patients (17 families) with negative molecular diagnostics for non-syndromic hearing loss (gene panel analysis) were included based on a positive family history with a similar type of hearing loss. Additional genetic testing was performed using a whole exome sequencing panel (WESHL panel v2.0) in four families with the strongest likelihood of genetic hearing impairment. In this cohort (n = 21), the severity of hearing loss was most commonly moderate (52%). Additional genetic testing revealed pathogenic copy number variants in the STRC gene in two families. In summary, regular re-evaluation of hearing loss patients with presumably genetic etiology after negative molecular diagnostics is recommended, as we might miss newly discovered deafness genes. The switch from gene panel analysis to whole exome sequencing or whole genome sequencing for the testing of congenital hearing loss seems promising. [ABSTRACT FROM AUTHOR]

Background Biallelic pathogenic variants in the ATP-binding cassette subfamily C member 6 (ABCC6) gene cause pseudoxanthoma elasticum, a multisystemic ectopic calcification disorder, while heterozygous ABCC6 variants are associated with an increased risk of cardiovascular and cerebrovascular disease. As the prevalence of pathogenic ABCC6 variants in the general population is estimated at ~1%, identifying additional ABCC6-related (sub)clinical manifestations in heterozygous carriers is of the utmost importance to reduce this burden of disease. Here, we present a large Belgian cohort of heterozygous ABCC6 carriers with comprehensive clinical, biochemical and imaging data. Based on these results, we formulate clinical practice guidelines regarding screening, preventive measures and follow-up of ABCC6 carriers. Methods The phenotype of 56 individuals carrying heterozygous pathogenic ABCC6 variants was assessed using clinical (eg, detailed ophthalmological examinations), biochemical, imaging (eg, cardiovascular and abdominal ultrasound) and genetic data. Clinical practice guidelines were then drawn up. Results We found that ABCC6 heterozygosity is associated with distinct retinal alterations (’comet- like’) (24%), high prevalence of hypercholesterolaemia (>75%) and diastolic dysfunction (33%), accelerated lower limb atherosclerosis and medial vascular disease, abdominal organ calcification (26%) and testicular microlithiasis (28%), though with highly variable expression. Conclusion In this study, we delineated the multisystemic ABCC6 heterozygosity phenotype characterised by retinal alterations, aberrant lipid metabolism, diastolic dysfunction and increased vascular, abdominal and testicular calcifications. Our clinical practice guidelines aimed to improve early diagnosis, treatment and follow-up of ABCC6-related health problems. [ABSTRACT FROM AUTHOR]

Study Question: What is the frequency of PLCZ1 , ACTL7A , and ACTL9 variants in male patients showing fertilization failure after ICSI, and how effective is assisted oocyte activation (AOA) for them?, Summary Answer: Male patients with fertilization failure after ICSI manifest variants in PLCZ1 (29.09%), ACTL7A (14.81%), and ACTL9 (3.70%), which can be efficiently overcome by AOA treatment with ionomycin., What Is Known Already: Genetic variants in PLCZ1 , and more recently, in ACTL7A , and ACTL9 male genes, have been associated with total fertilization failure or low fertilization after ICSI. A larger patient cohort is required to understand the frequency at which these variants occur, and to assess their effect on the calcium ion (Ca 2+ ) release during oocyte activation. AOA, using ionomycin, can restore fertilization and pregnancy rates in patients with PLCZ1 variants, but it remains unknown how efficient this is for patients with ACTL7A and ACTL9 variants., Study Design Size Duration: This prospective study involved two patient cohorts. In the first setting, group 1 (N = 28, 2006-2020) underwent only PLCZ1 genetic screening, while group 2 (N = 27, 2020-2023) underwent PLCZ1, ACTL7A , and ACTL9 genetic screening. Patients were only recruited when they had a mean fertilization rate of ≤33.33% in at least one ICSI cycle with at least four MII oocytes. Patients underwent a mouse oocyte activation test (MOAT) and at least one ICSI-AOA cycle using calcium chloride (CaCl 2 ) injection and double ionomycin exposure at our centre. All patients donated a saliva sample for genetic screening and a sperm sample for further diagnostic tests, including Ca 2+ imaging., Participants/materials Setting Methods: Genetic screening was performed via targeted next-generation sequencing. Identified variants were classified by applying the revised ACMG guidelines into a Bayesian framework and were confirmed by bidirectional Sanger sequencing. If variants of uncertain significance or likely pathogenic or pathogenic variants were found, patients underwent additional determination of the sperm Ca 2+ -releasing pattern in mouse (MOCA) and in IVM human (HOCA) oocytes. Additionally, ACTL7A immunofluorescence and acrosome ultrastructure analyses by transmission electron microscopy (TEM) were performed for patients with ACTL7A and/or ACTL9 variants., Main Results and the Role of Chance: Overall, the frequency rate of PLCZ1 variants was 29.09%. Moreover, 14.81% of patients carried ACTL7A variants and 3.70% carried ACTL9 variants. Seven different PLCZ1 variants were identified (p.Ile74Thr, p.Gln94*, p.Arg141His, p.His233Leu, p.Lys322*, p.Ile379Thr, and p.Ser500Leu), five of which are novel. Interestingly, PLCZ1 variants p.Ser500Leu and p.His233Leu occurred in 14.55% and 9.09% of cases. Five different variants were found in ACTL7A (p.Tyr183His, p.Gly214Ser, p.Val340Met, p.Ser364Glnfs*9, p.Arg373Cys), four of them being identified for the first time. A novel variant in ACTL9 (p.Arg271Pro) was also described. Notably, both heterozygous and homozygous variants were identified.The MOCA and HOCA tests revealed abnormal or absent Ca 2+ release during fertilization in all except one patient, including patients with PLCZ1 heterozygous variants. TEM analysis revealed abnormal acrosome ultrastructure in three patients with ACTL7A variants, but only patients with homozygous ACTL7A variants showed reduced fluorescence intensity in comparison to the control.AOA treatment significantly increased the fertilization rate in the 19 patients with detected variants (from 11.24% after conventional ICSI to 61.80% after ICSI-AOA), as well as positive hCG rate (from 10.64% to 60.00%) and live birth rate (from 6.38% to 37.14%), resulting in 13 healthy newborns. In particular, four live births and two ongoing pregnancies were produced using sperm from patients with ACTL7A variants., Limitations Reasons for Caution: Genetic screening included exonic and outflanking intronic regions, which implies that deep intronic variants were missed. In addition, other male genes or possible female-related factors affecting the fertilization process remain to be investigated., Wider Implications of the Findings: Genetic screening of PLCZ1 , ACTL7A , and ACTL9 offers a fast, cost-efficient, and easily implementable diagnostic test for total fertilization failure or low fertilization after ICSI, eliminating the need for complex diagnostic tests like MOAT or Ca 2+ analysis. Nonetheless, HOCA remains the most sensitive functional test to reveal causality of uncertain significance variants. Interestingly, heterozygous PLCZ1 variants are sufficient to cause inadequate Ca 2+ release during ICSI. Most importantly, AOA treatment using CaCl 2 injection followed by double ionomycin exposure is highly effective for this patient group, including those with ACTL7A variants, who also display a Ca 2+ -release deficiency., Study Funding/competing Interests: This study was supported by the Flemish Fund for Scientific Research (FWO) (TBM-project grant T002223N awarded to B.H.) and by the Special Research Fund (BOF) (starting grant BOF.STG.2021.0042.01 awarded to B.H.). A.C.B., R.R.G., C.C., E.V.D.V., A.R., D.S., L.L., P.C., S.S., A.B., and F.V.M. have nothing to disclose. B.H. reports a research grant from FWO and BOF, and reports being a board member of the Belgian Ethical Committee on embryo research., Trial Registration Number: N/A., Competing Interests: A.C.B., R.R.G., C.C., E.V.D.V., A.R., D.S., L.L., P.C., S.S., A.B., and F.V.M. have nothing to disclose. B.H. reports a research grant from the FWO and BOF and reports being a board member of the Belgian Ethical Committee on embryo research., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology.)

Arrhythmogenic cardiomyopathy is a severe genetic heart muscle disease characterized by fibro-fatty replacement of the myocardium. Pathogenic variants causal for this disease are mainly located in desmosomal genes, including desmoplakin (DSP). Renal epithelial cells were isolated from a patient carrying the heterozygous c.817C>T (p.Q273*, nonsense) pathogenic variant in DSP, and subsequently reprogrammed using the Cytotune®-iPS 2.0 Sendai Reprogramming Kit. An isogenic control line was generated using CRISPR/Cas9 genome editing. The resulting induced pluripotent stem cell lines were characterized and displayed the required traits for in vitro disease modeling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)