Clinical spectrum of females with HCCS mutation: from no clinical signs to a neonatal lethal form of the microphthalmia with linear skin defects (MLS) syndrome

Background: Segmental Xp22.2 monosomy or a heterozygous HCCS mutation is associated with the microphthalmia with linear skin defects (MLS) or MIDAS (microphthalmia, dermal aplasia, and sclerocornea) syndrome, an X-linked disorder with male lethality. HCCS encodes the holocytochrome c-type synthase involved in mitochondrial oxidative phosphorylation (OXPHOS) and programmed cell death. Methods: We characterized the X-chromosomal abnormality encompassing HCCS or an intragenic mutation in this gene in six new female patients with an MLS phenotype by cytogenetic analysis, fluorescence in situ hybridization, sequencing, and quantitative real-time PCR. The X chromosome inactivation (XCI) pattern was determined and clinical data of the patients were reviewed. Results: Two terminal Xp deletions of ≥11.2 Mb, two submicroscopic copy number losses, one of ~850 kb and one of ≥3 Mb, all covering HCCS, 1 nonsense, and one mosaic 2-bp deletion in HCCS are reported. All females had a completely (>98:2) or slightly skewed (82:18) XCI pattern. The most consistent clinical features were microphthalmia/anophthalmia and sclerocornea/corneal opacity in all patients and congenital linear skin defects in 4/6. Additional manifestations included various ocular anomalies, cardiac defects, brain imaging abnormalities, microcephaly, postnatal growth retardation, and facial dysmorphism. However, no obvious clinical sign was observed in three female carriers who were relatives of one patient. Conclusion: Our findings showed a wide phenotypic spectrum ranging from asymptomatic females with an HCCS mutation to patients with a neonatal lethal MLS form. Somatic mosaicism and the different ability of embryonic cells to cope with an OXPHOS defect and/or enhanced cell death upon HCCS deficiency likely underlie the great variability in phenotypes

Genetics of preeclampsia: paradigm shifts

Segregation of preeclampsia into early-onset, placental and late-onset, maternal subtypes along with the acknowledgement of the contribution of epigenetics in placentally expressed genes proved to be a key first step in the identification of essential gene variants associated with preeclampsia. Application of this insight to other populations and related pregnancy-induced syndromes, such as HELLP, and acknowledgment of the features shared between chromosomal loci associated with preeclampsia in different populations provide the rationale for new strategies for the identification of susceptibility genes and for new and more effective diagnostic strategie

NIPT-based screening for Down syndrome and beyond: what do pregnant women think?

The aim of the study is to study pregnant women's views on noninvasive prenatal testing (NIPT) for Down syndrome and the potential to test for a broader range of conditions. An online questionnaire available on the Dutch pregnancy fair website was completed by 381 pregnant women. Of the women, 51% expressed interest in having NIPT, including 33% of women who had declined first-trimester screening. The majority (73%) thought that the uptake of screening would increase with NIPT. Most women agreed that testing for life-threatening (89%), severe physical (79%), or severe mental (76%) disorders should be offered. A minority (29%) felt that prenatal screening should also be offered for late-onset disorders. Most (41%) preferred to have a free choice from a list of disorders, 31% preferred a 'closed offer', and 26% preferred choosing between packages of disorders. Although most women (76%) thought that screening for a broad range of conditions would avoid much suffering, 39% feared that it would confront couples with choices, the implications of which would be difficult to grasp. The results suggest that the uptake of screening will increase with NIPT. If NIPT will be offered for a broad range of conditions, it is crucial to find a way that facilitates rather than undermines well-informed decision-makin

De novo mutations in the <i>SET</i> nuclear proto-oncogene, encoding a component of the inhibitor of histone acetyltransferases (INHAT) complex in patients with nonsyndromic intellectual disability

The role of disturbed chromatin remodeling in the pathogenesis of intellectual disability (ID) is well established and illustrated by de novo mutations found in a plethora of genes encoding for proteins of the epigenetic regulatory machinery. We describe mutations in the “SET nuclear proto-oncogene” (SET), encoding a component of the “inhibitor of histone acetyltransferases” (INHAT) complex, involved in transcriptional silencing. Using whole exome sequencing, four patients were identified with de novo mutations in the SET gene. Additionally, an affected mother and child were detected who carried a frameshift variant in SET. Four patients were found in literature. The de novo mutations in patients affected all four known SET mRNA transcripts. LoF mutations in SET are exceedingly rare in the normal population and, if present, affect only one transcript. The pivotal role of SET in neurogenesis is evident from in vitro and animal models. SET interacts with numerous proteins involved in histone modification, including proteins encoded by known autosomal dominant ID genes, that is, EP300, CREBBP, SETBP1, KMT2A, RAC1, and CTCF. Our study identifies SET as a new component of epigenetic regulatory modules underlying human cognitive disorders, and as a first member of the Nucleosome Assembly Protein (NAP) family implicated in ID

CRTAP mutations in lethal and severe osteogenesis imperfecta: the importance of combining biochemical and molecular genetic analysis

Autosomal recessive lethal and severe osteogenesis imperfecta (OI) is caused by the deficiency of cartilage-associated protein (CRTAP) and prolyl-3-hydroxylase 1 (P3H1) because of CRTAP and LEPRE1 mutations. We analyzed five families in which 10 individuals had a clinical diagnosis of lethal and severe OI with an overmodification of collagen type I on biochemical testing and without a mutation in the collagen type I genes. CRTAP mutations not described earlier were identified in the affected individuals. Although it seems that one important feature of autosomal recessive OI due to CRTAP mutations is the higher consistency of radiological features with OI type II-B/III, differentiation between autosomal dominant and autosomal recessive OI on the basis of clinical, radiological and biochemical investigations proves difficult in the affected individuals reported here. These observations confirm that once a clinical diagnosis of OI has been made in an affected individual, biochemical testing for overmodification of collagen type I should always be combined with molecular genetic analysis of the collagen type I genes. If no mutations in the collagen type I genes are found, additional molecular genetic analysis of the CRTAP and LEPRE1 genes should follow. This approach will allow proper identification of the genetic cause of lethal or severe OI, which is important in providing prenatal diagnosis, preimplantation genetic diagnosis and estimating recurrence risk

Attitudes of pregnant women and male partners towards non-invasive prenatal testing and widening the scope of prenatal screening

Non-invasive prenatal testing (NIPT) and its potential to test for multiple disorders has received much attention. This study explores attitudes of women and men towards NIPT, and their views on widening the scope of prenatal testing in a country with a low uptake of prenatal screening (The Netherlands). Five focus groups with low-risk pregnant women (n=28), three focus groups with men (n=19) and 13 interviews with high- and low-risk pregnant women were conducted. Participants felt that current prenatal screening has great disadvantages such as uncertain results and risk of miscarriage from follow-up diagnostics. Characteristics of NIPT (accurate, safe and early testing) could therefore diminish these disadvantages of prenatal screening and help lower the barrier for participation. This suggests that NIPT might allow couples to decide about prenatal testing based mostly on their will to test or not, rather than largely based on fear of miscarriage risk or the uncertainty of results. The lower barrier for participation was also seen as a downside that could lead to uncritical use or pressure to test. Widening the scope of prenatal testing was seen as beneficial for severe disorders, although it was perceived difficult to determine where to draw the line. Participants argued that there should be a limit to the scope of NIPT, avoiding testing for minor abnormalities. The findings suggest that NIPT could enable more meaningful decision-making for prenatal screening. However, to ensure voluntary participation, especially when testing for multiple disorders, safeguards on the basis of informed decision-making will be of utmost importance.European Journal of Human Genetics advance online publication, 19 March 2014; doi:10.1038/ejhg.2014.32