Florence Amblard

Population screening for aneuploidy using maternal age and ultrasound.

The coexistence of an epidemiological register and a multidisciplinary centre for prenatal diagnosis prompted us to report data collected during six years (1990–1995) in Isère county on prenatally detected chromosomal aberrations. During the whole study period prenatal diagnosis strategy towards chromosome aberrations was based solely on maternal age and ultrasound examination. Results showed a respective contribution of one‐third/two‐thirds for the two detection modes (maternal age/ultrasound signs). From 1990 to 1995 a significant increase in the proportion of prenatally detected autosomal aneuploidy was observed, from 52 per cent to 75 per cent (P<0·001). This significant variation was mainly due to an increase in the proportion of prenatally detected trisomy 21 cases, and to an increase in the proportion of aberrations which were detected through first trimester ultrasound examination. The highest positive predictive values were observed for polymalformation, cardiac anomalies and cystic hygroma ultrasound signs (51 per cent, 21 per cent and 26 per cent, respectively). Our results for trisomy 21 are close to those obtained in other studies, even when prenatal strategies are different. Their interest lies in the fact that they can be considered as a reference level of prenatal diagnosis efficiency due to a strategy based on maternal age and ultrasound signs, a level which has to be taken into account when evaluating the benefits of additional serum screening policies in other studies.

A French multicenter study of over 700 patients with 22q11 deletions diagnosed using FISH or aCGH

Although 22q11.2 deletion syndrome (22q11.2DS) is the most recurrent human microdeletion syndrome associated with a highly variable phenotype, little is known about the condition’s true incidence and the phenotype at diagnosis. We performed a multicenter, retrospective analysis of postnatally diagnosed patients recruited by members of the Association des Cytogénéticiens de Langue Française (the French-Speaking Cytogeneticists Association). Clinical and cytogenetic data on 749 cases diagnosed between 1995 and 2013 were collected by 31 French cytogenetics laboratories. The most frequent reasons for referral of postnatally diagnosed cases were a congenital heart defect (CHD, 48.6%), facial dysmorphism (49.7%) and developmental delay (40.7%). Since 2007 (the year in which array comparative genomic hybridization (aCGH) was introduced for the routine screening of patients with intellectual disability), almost all cases have been diagnosed using FISH (96.1%). Only 15 cases (all with an atypical phenotype) were diagnosed with aCGH; the deletion size ranged from 745 to 2904 kb. The deletion was inherited in 15.0% of cases and was of maternal origin in 85.5% of the latter. This is the largest yet documented cohort of patients with 22q11.2DS (the most commonly diagnosed microdeletion) from the same population. French cytogenetics laboratories diagnosed at least 108 affected patients (including fetuses) per year from among a national population of ∼66 million. As observed for prenatal diagnoses, CHDs were the most frequently detected malformation in postnatal diagnoses. The most common CHD in postnatal diagnoses was an isolated septal defect.

17p13.1 microduplication in a boy with Silver-Russell syndrome features and intellectual disability

Many deletions of chromosome 17p13.1 have been described, but very few 17p13.1 duplications have been reported yet. Here, we describe the genotype and phenotype of a boy with a duplication of this region. The main clinical features are mild intellectual deficiency, growth retardation, and a typical Silver–Russell syndrome (SRS) appearance with small triangular face, prominent forehead, micrognathia, low‐set ears, and clinodactyly. Array‐CGH revealed a 586 kb duplication containing many genes with a high neuronal expression. Interestingly, this region covers the minimal critical region including all candidate genes suggested to explain the 17p13.1 microdeletion syndrome. In the neighboring region 17p13.3, deletions and duplications of the same region are each responsible of a specific phenotype. Future case descriptions will show if a similar mechanism applies to the region 17p13.1. The 17p13.1 region contains interesting putative candidate genes that might be involved in the SRS etiology. Additional data are needed to verify the significance of this aberration.

Pregnancy outcomes of prenatally diagnosed Turner syndrome: a French multicenter retrospective study including a series of 975 cases

The objectives of this study were to report pregnancy outcomes after prenatal diagnosis of Turner syndrome (TS) and to compare and assess termination of pregnancy rates during two periods. The intervals selected were before and after 1997 when multidisciplinary centers for prenatal diagnosis (MCPDs) were established in France.

Functional and genetic characterization of two extremely rare cases of Williams–Beuren Syndrome associated with chronic granulomatous disease

Williams–Beuren syndrome (WBS) is a neurodevelopmental disorder with multi-systemic manifestations, caused by a heterozygous segmental deletion of 1.55–1.83 Mb at chromosomal band 7q11.23. The deletion can include the NCF1 gene that encodes the p47phox protein, a component of the leukocyte NADPH oxidase enzyme, which is essential for the defense against microbial pathogens. It has been postulated that WBS patients with two functional NCF1 genes are more susceptible to occurrence of hypertension than WBS patients with only one functional NCF1 gene. We now describe two extremely rare WBS patients without any functional NCF1 gene, because of a mutation in NCF1 on the allele not carrying the NCF1-removing WBS deletion. These two patients suffer from chronic granulomatous disease with increased microbial infections in addition to WBS. Interestingly, one of these patients did suffer from hypertension, indicating that other factors than NADPH oxidase in vascular tissue may be involved in causing hypertension.

Maternal complex chromosomal rearrangement leads to TCF12 microdeletion in a patient presenting with coronal craniosynostosis and intellectual disability.

We report on a young child with intellectual disability and unilateral coronal craniosynostosis leading to craniofacial malformations. Standard karyotype showed an apparently balanced translocation between chromosomes 2 and 15 [t(2;15)(q21;q21.3)], inherited from his mother. Interestingly, array‐CGH 180K showed a 3.64 Mb de novo deletion on chromosome 15 in the region 15q21.3q22.2, close to the chromosome 15 translocation breakpoints. This deletion leads to haploinsufficiency of TCF12 gene that can explain the coronal craniosynostosis described in the patient. Additional FISH analyses showed a complex balanced maternal chromosomal rearrangement combining the reciprocal translocation t(2;15)(q21;q21.3), and an insertion of the 15q22.1 segment into the telomeric region of the translocated 15q fragment. The genomic imbalance in the patient is likely caused by a crossing‐over that occurs in the recombination loop formed during the maternal meiosis resulting in the deletion of the inserted fragment. This original case of a genomic microdeletion of TCF12 exemplifies the importance of array‐CGH in the clinical investigation of apparently balanced rearrangements but also the importance of FISH analysis to identify the chromosomal mechanism causing the genomic imbalance.

PBX1 haploinsufficiency leads to syndromic congenital anomalies of the kidney and urinary tract (CAKUT) in humans

Background Congenital anomalies of the kidney and urinary tract (CAKUT) represent a significant healthcare burden since it is the primary cause of chronic kidney in children. CNVs represent a recurrent molecular cause of CAKUT but the culprit gene remains often elusive. Our study aimed to define the gene responsible for CAKUT in patients with an 1q23.3q24.1 microdeletion. Methods We describe eight patients presenting with CAKUT carrying an 1q23.3q24.1 microdeletion as identified by chromosomal microarray analysis (CMA). Clinical features were collected, especially the renal and urinary tract phenotype, and extrarenal features. We characterised PBX1 expression and localisation in fetal and adult kidneys using quantitative RT-PCR and immunohistochemistry. Results We defined a 276-kb minimal common region (MCR) that only overlaps with the PBX1 gene. All eight patients presented with syndromic CAKUT. CAKUT were mostly bilateral renal hypoplasia (75%). The most frequent extrarenal symptoms were developmental delay and ear malformations. We demonstrate that PBX1 is strongly expressed in fetal kidneys and brain and expression levels decreased in adult samples. In control fetal kidneys, PBX1 was localised in nuclei of medullary, interstitial and mesenchymal cells, whereas it was present in endothelial cells in adult kidneys. Conclusions Our results indicate that PBX1 haploinsufficiency leads to syndromic CAKUT as supported by the Pbx1-null mice model. Correct PBX1 dosage appears to be critical for normal nephrogenesis and seems important for brain development in humans. CMA should be recommended in cases of fetal renal anomalies to improve genetic counselling and pregnancy management.

7p22.3 microdeletion disrupting SNX8 in a patient presenting with intellectual disability but no tetralogy of Fallot

© 2014 Wiley Periodicals, Inc.

Interphase fluorescent in situ hybridization detection of the 7q11.23 chromosomal inversion in a clinical laboratory: automated versus manual scoring.

*Corresponding author: Gwena ë l Nadeau , Unit é Fonctionnelle de Cytog é n é tique, Centre Hospitalier de Valence, 179 Boulevard du Mar é chal Juin, 26953 Valence Cedex 9, France, Phone: + 33 475757297, Fax: + 33-475757161, E-mail: gnadeau@ch-valence.fr Gwena ë l Nadeau, Charles Coutton, Florence Amblard, Gabrielle Michalowicz, Sylvie Frasca , Fran ç oise Devillard , V é ronique Satre and Pierre-Simon Jouk: Centre Hospitalier Universitaire de Grenoble , D é partement de G é n é tique et Procr é ation, Grenoble , France Charles Coutton and V é ronique Satre: Laboratoire AGIM , CNRS FRE3405, Equipe “ G é n é tique, Infertilit é et Th é rapeutiques ” , La Tronche, France, Universit é Joseph Fourier, Grenoble , France Gabrielle Michalowicz , Arnold Fertin , Yves Usson and Pierre-Simon Jouk: UJF-Grenoble1 , TIMC-IMAG, DyCTIM Team, CNRS-UJF UMR 5525, Grenoble , France

190‐kb duplication in 1p36.11 including PIGV and ARID1A genes in a girl with intellectual disability and hexadactyly

To the Editor : Coffin–Siris syndrome (CSS) is a rare autosomal dominant syndrome characterized by intellectual disability, growth deficiency, microcephaly, coarse facial features and hypoplastic nail of the fifth finger and/or toe (1). Germline mutations in ARID1A, one of the SWItch/Sucrose NonFermenting complex subunit genes, were recently identified in about 90% of CSS patients (2). Hyperphosphatasia mental retardation syndrome (HPMR), also known as Mabry syndrome, is an autosomal recessive syndrome which was first related to the triad: developmental disability, seizures and hyperphosphatasia manifesting in the first year of life (3). Within this broad phenotype, Thompson et al. delineated a specific clinical entity characterized by facial gestalt including long palpebral fissures, a broad nasal bridge and tip, a tented mouth, and brachytelephalangy (4). Homozygous and compound heterozygous missense mutations in PIGV , the first gene associated with Mabry syndrome and encoding the second mannosyltransferase in the GPI-anchor biosynthesis pathway, were identified using wholeexome sequencing in HPMR families (5). Here, we report for the first time, the clinical and molecular characterization of a patient with de novo 1p36.11 microduplication including PIGV and ARID1A. The propositus is a girl born at 41 weeks after a normal delivery from non-consanguineous healthy parents with no family history of congenital anomalies or developmental delay. Prenatal ultrasonography performed in the 22nd week of gestation had revealed a four-limb postaxial hexadactyly. The supernumerary digits were removed by surgery at 4 months (Fig. 1a,b). Her birth weight was 3180 g (> −1 SD), length 46 cm (−2 SD), and head circumference 33 cm (−1 SD). To date (3 years), her height is 87 cm (−2 SD), weight 11 kg (−2 SD), and head circumference 44 cm (< −2 SD). At 9 months old, she presented repetitive and stereotyped upper limbs movements (see Video S1, Supporting information). She had facial dysmorphic features including broad nasal bridge and tip, short philtrum, thin upper lip, abnormal ears, spare scalp hairs (Fig. 1c,d) associated with severe microcephaly of prenatal onset and overlapping toes (Fig. 1b). She also suffered of constipation, gastro-oesophageal reflux, feeding problems and eczema in relation to a cow’s milk protein allergy. She had motor skills delay with no sign of walking or crawling at 36 months. The sitting position was acquired at the age of 12 months. She had severe developmental and speech delay with only two words at 2 years old. Complete clinical and radiological examinations showed no specific abnormalities at the age of 3. Serum alkaline phosphatase level was normal (180 IU/l). No lysosomal storage and intracellular inclusions in cultured fibroblasts were observed after periodic acid Schiff reaction like those reported in the Mabry syndrome (6). It is notable that a duplication in PIGV – one of genes inactivated in Mabry syndrome – does not result in alterations in alkaline phosphatase activity in 1p36.11 duplication syndrome. Array comparative genomic hybridization analyses (CGH Microarray Kit 180K, Agilent, CA) showed a 190-kb duplication in 1p36.11 extending from base 27,001,256 to 27,190,935 (NCBI, hg 19) from the 1p telomere (Fig. 1e). No other abnormalities larger than three probes were observed, excluding well-known benign copy number variation reported in the Database of Genomic Variants (DGV). Custom multiplex ligation-dependent probe amplification (MLPA) analysis confirmed the duplication in the patient (Fig. 1f) and analysis of the parents revealed normal MLPA profiles. The fluorescent in situ hybridization analysis showed the tandem duplication in the 1p36.11 region (Fig. 1g). Reverse transcriptase multiplex ligation-dependent probe amplification analysis of mRNAs in fibroblast cell revealed that expression of ARID1A and PIGV was respectively about 1.5and 3-fold higher compared to controls (Fig. 1h). In this de novo 190-kb duplicated region, four known protein-coding genes are listed in NCBI build 37.2. Among them, ARID1A, PIGV , ZDHHC18 , SFN are completely duplicated. ZDHHC18 , whose function is unknown, is expressed predominantly in lymphoid tissue. SFN encodes for the stratifin involved in multiple cellular processes and commonly silenced in various cancers (7). In DGV, variation 4218 described many copy number variations including ZDHHC18 and SFN , suggesting that ZDHHC18 and SFN duplications are likely benign, although we cannot formally exclude their contribution in the phenotype.