Genetic counselling difficulties and ethical implications of incidental findings from array-CGH: a 7-year national survey.

Microarray-based comparative genomic hybridization (aCGH) is commonly used in diagnosing patients with intellectual disability (ID) with or without congenital malformation. Because aCGH interrogates with the whole genome, there is a risk of being confronted with incidental findings (IF). In order to anticipate the ethical issues of IF with the generalization of new genome-wide analysis technologies, we questioned French clinicians and cytogeneticists about the situations they have faced regarding IF from aCGH. Sixty-five IF were reported. Forty corresponded to autosomal dominant diseases with incomplete penetrance, 7 to autosomal dominant diseases with complete penetrance, 14 to X-linked diseases, and 4 were heterozygotes for autosomal recessive diseases with a high prevalence of heterozygotes in the population. Therapeutic/preventive measures or genetic counselling could be argued for all cases except four. These four IF were intentionally not returned to the patients. Clinicians reported difficulties in returning the results in 29% of the cases, mainly when the question of IF had not been anticipated. Indeed, at the time of the investigation, only 48% of the clinicians used consents mentioning the risk of IF. With the emergence of new technologies, there is a need to report such national experiences; they show the importance of pre-test information on IF.

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

OBJECTIVES: 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. METHODS: A database of 975 cases of TS diagnosed between 1980 and 2012 was created from 21 French cytogenetics laboratories. For each case, the karyotype indication, maternal age, year of prenatal testing, sampling procedure, karyotype, associated ultrasound findings, and outcomes were recorded. RESULTS: Karyotypes were mainly performed because of abnormal sonographic findings (84%). Before 1997, there were no changes in the rate of termination (90%) of affected fetuses. After 1997, the rate fell to 80%. This decrease was mainly observed in cases of mosaicism, incidental diagnosis, and in later gestations. US abnormalities were more likely to be associated with a full 45,X karyotype. CONCLUSION: There was an evolution in the way genetic counseling was performed following prenatal diagnosis of Turner syndrome that coincided with the opening of MCPDs in France. This resulted in a decrease in the rate of termination of affected fetuses.

A French collaborative survey of 272 fetuses with 22q11.2 deletion: ultrasound findings, fetal autopsies and pregnancy outcomes.

OBJECTIVE: The 22q11.2 deletion (del22q11.2) is one of the most common microdeletions. We performed a collaborative, retrospective analysis in France of prenatal diagnoses and outcomes of fetuses carrying the del22q11.2. METHODS: A total of 272 fetuses were included. Data on prenatal diagnosis, ultrasound findings, pathological features, outcomes and inheritance were analyzed. RESULTS: The mean time of prenatal diagnosis was 25.6 ± 6 weeks of gestation. Most of the diagnoses (86.8%) were prompted by abnormal ultrasound findings [heart defects (HDs), in 83.8% of cases]. On fetal autopsy, HDs were again the most common disease feature, but thymus, kidney abnormalities and facial dysmorphism were also described. The deletion was inherited in 27% of cases. Termination of pregnancy (TOP) occurred in 68.9% of cases and did not appear to depend on the inheritance status. However, early diagnosis was associated with a higher TOP rate. CONCLUSION: This is the largest cohort of prenatal del22q11.2 diagnoses. As in postnatally diagnosed cases, HDs were the most frequently observed abnormalities. However, thymus and kidney abnormalities and polyhydramnios should also be screened for in the prenatal diagnosis of del22q11.2. Only the time of diagnosis appeared to be strongly associated with the pregnancy outcome: the earlier the diagnosis, the higher the TOP rate.

Pregnancy outcomes in 188 French cases of prenatally diagnosed Klinefelter syndrome.

BACKGROUND: Klinefelter syndrome (KS), a common sex chromosome aneuploidy (47,XXY) is diagnosed prenatally with an incidence of 0.15%. The diagnosis is generally incidental, since there are no typical malformations on ultrasound (US). Once detected, genetic counseling is often difficult and the parents' decision to continue or terminate the pregnancy is greatly dependent on the amount and nature of the information provided. We sought to assess the pregnancy outcomes (i.e. continuation versus termination) and the influence of multidisciplinary centers for prenatal diagnosis on parental decisions in cases of KS. METHODS: From 1985 to 2009, 188 prenatal diagnoses of KS were made by 11 participating laboratories in mainland France. In each case, the karyotype indication, parental ages, year of prenatal testing, sampling procedure, karyotype, associated US findings and outcome were recorded. RESULTS AND CONCLUSIONS: The pregnancy termination rate declined markedly over time, from 46.9% before 1997 to 11.6% thereafter, in line with the introduction of new legislation on prenatal diagnosis for medical reasons and, more specifically, the creation of multidisciplinary prenatal diagnosis centers. However, an additional microdeletion in one KS infant who exhibited echogenic bowel on US was unfortunately diagnosed postnatally. This raises the question as to whether array comparative genomic hybridization should be prenatally advised when US abnormalities are detected, in line with advice for fetuses with a normal karyotype.

Renal insufficiency, a frequent complication with age in oral-facial-digital syndrome type I.

The oral-facial-digital syndrome type I (OFD I) is characterized by multiple congenital malformations of the face, oral cavity and digits. A polycystic kidney disease (PKD) is found in about one-third of patients but long-term outcome and complications are not well described in the international literature. Renal findings have been retrospectively collected in a cohort of 34 females all carrying a pathogenic mutation in the OFD1 gene with ages ranging from 1 to 65 years. Twelve patients presented with PKD - 11/16 (69%) if only adults were considered -with a median age at diagnosis of 29 years [IQR (interquartile range) = (23.5-38)]. Among them, 10 also presented with renal impairment and 6 were grafted (median age = 38 years [IQR = (25-48)]. One grafted patient under immunosuppressive treatment died from a tumor originated from a native kidney. The probability to develop renal failure was estimated to be more than 50% after the age of 36 years. Besides, neither genotype-phenotype correlation nor clinical predictive association with renal failure could be evidenced. These data reveal an unsuspected high incidence rate of the renal impairment outcome in OFD I syndrome. A systematic ultrasound (US) and renal function follow-up is therefore highly recommended for all OFD I patients.

Fluorescence in situ hybridization analysis of 110 hematopoietic disorders with chromosome 5 abnormalities: do de novo and therapy-related myelodysplastic syndrome-acute myeloid leukemia actually differ?

A retrospective cytogenetic study of acute myeloid leukemias (AML) and myelodysplastic syndromes (MDS) was conducted by the Groupe Francophone de Cytogénétique Hématologique (GFCH) to evaluate the structural abnormalities of chromosome 5 associated with other chromosomal abnormalities, in particular of chromosome 7, in these pathologies. In all, 110 cases of AML/MDS were recruited based on the presence of chromosome 5 abnormalities under conventional cytogenetics and supplemented by a systematic fluorescence in situ hybridization study of chromosomes 5 and 7. The abnormalities of the long arm of chromosome 5 (5q) were deletions of various sizes and sometimes cryptic. The 5q abnormalities were associated with translocations in 54% of cases and were simple deletions in 46%. In 68% of cases, 5q deletions were associated with chromosome 7 abnormalities, and 90% of these presented a complex karyotype. Of the 110 patients, 28 had a hematopoietic disorder secondary to chemotherapy, radiotherapy, or both. Among 82 patients with de novo AML/MDS, 63 were older than 60 years. Chromosomal abnormalities often associated hypodiploidy and chromosome 5 and 7 abnormalities in complex karyotypes, features resembling those of secondary hemopathies. Systematic investigation of the exposure to mutagens and oncogenes is thus essential to specify the factors potentially involved in MDS/AML with 5q abnormalities.

Mutations in PHF8 are associated with X linked mental retardation and cleft lip/cleft palate.

Truncating mutations were found in the PHF8 gene (encoding the PHD finger protein 8) in two unrelated families with X linked mental retardation (XLMR) associated with cleft lip/palate (MIM 300263). Expression studies showed that this gene is ubiquitously transcribed, with strong expression of the mouse orthologue Phf8 in embryonic and adult brain structures. The coded PHF8 protein harbours two functional domains, a PHD finger and a JmjC (Jumonji-like C terminus) domain, implicating it in transcriptional regulation and chromatin remodelling. The association of XLMR and cleft lip/palate in these patients with mutations in PHF8 suggests an important function of PHF8 in midline formation and in the development of cognitive abilities, and links this gene to XLMR associated with cleft lip/palate. Further studies will explore the specific mechanisms whereby PHF8 alterations lead to mental retardation and midline defects.

Six cases of cryptic subtelomeric translocations in four families: the use of subtelomeric FISH probes as a diagnostic tool.

Finding the diagnosis in children with mental retardation and a normal karyotype, whether or not associated with dysmorphic features, is important for defining an eventual syndrome and for genetic counselling of the families. Telomeric re-arrangements may be a common and underestimated-to-date cause of non-syndromic mental retardation. Using a FISH-based approach combining subtelomeric probes, we report the detection of 4 cases of cryptic translocations t(2;10)(p25.3;q26.3), t(4;17)(p16.2;q25), t(4;20)(p16.2;q13) and t(5;7)(p15.3;q36) associated with MR and dysmorphic features. We discuss the usefulness of subtelomeric FISH in children with unexplained delayed psychomotor development, when the genetic cause remains unknown and the karyotype is normal.

[Molecular chromosomic genetics in prenatal and perinatal diagnosis of chromosomal anomalies and genetic diseases]. / Apport de la génétique chromosomique moléculaire au diagnostic prénatal et périnatal des anomalies chromosomiques et des maladies géniques.

Prenatal and perinatal diagnosis needs a rapid, accurate and overall genome analysis. Molecular chromosomic techniques such as fluorescent in situ hybridization (FISH) with "cold" (not radioactively labeled) probes combine techniques of both conventional chromosome banding and molecular biology. FISH is a powerful tool for detecting some genetic diseases as well as microscopic or submicroscopic chromosome rearrangements, in metaphases cells or interphase nuclei.

A large multiple endocrine neoplasia type 1 family with clinical expression suggestive of anticipation.

We describe a large multigenerational multiple endocrine neoplasia Type 1 (MEN1) family with clinical expression suggestive of anticipation. In the second and third generations, two deceased obligate gene carriers died at the ages of 85 and 76 without the history of MEN1, whereas two other living gene carriers above the age of 65 have had no clinical evidence of MEN1 to date. In the fourth generation, eight members were affected, with four having severe MEN1-related and atypical malignancies: a case of metastatic endocrine pancreatic tumor, two cases of metastatic thymic carcinoids, and a case of spinal ependymoma. In the fifth generation, all five patients were below the age of 22 when the disease was detected. MEN1 was confirmed in the family by linkage analysis using MEN1-linked microsatellite markers and by identification of a nonsense mutation in the MEN1/menin gene. Alleotyping showed loss of heterozygosity (LOH) involving the wild-type alleles in seven tumors in the family including the ependymoma, which is the first MEN1-related case that shows genetic abnormality in chromosome 11q13, suggesting that MEN1 gene might be involved in the tumorigenesis of a subset of ependymomas. In relation to clinical anticipation, repeated expansion studies were carried out but failed to detect any expansion. We conclude that this is a unique MEN1 family and that an unknown genetic mechanism might be contributing to the anticipation phenomenon. We demonstrate in this family that all gene carriers, including the very young members, will need close and careful follow-up.

High resolution comparative genomic hybridisation analysis reveals imbalances in dyschromosomal patients with normal or apparently balanced conventional karyotypes.

A sensitive technique is needed for screening whole genome imbalances in dyschromosomal patients when G-banding shows normal karyotypes or apparently balanced translocations. In this study we performed highly sensitive comparative genomic hybridisation analysis on a number of such cases and revealed chromosomal imbalances in all.

A multicentric study of 41 cases of B-prolymphocytic leukemia: two evolutive forms.

B-prolymphocytic leukemia (B-PLL) is an infrequent disease with a poor prognosis. We present the clinical and biological features of 41 patients. Median age was 67 years [42-89] and male-female sex ratio was 2.4. The immunophenotyping revealed B-cell phenotype, with a high level expression of surface IgM and/or IgD in all cases, FMC7+ in 76 % of cases and CD5+ in 67%. Marked spontaneous in-vitro apoptosis was observed in most cases tested (n = 12). The median overall survival time was 5 years and the event-free survival time was 37 months. As detected by univariate and multivariate analysis, the only variables associated with a poor prognosis were advanced age and anemia. No significant difference was observed between de novo PLL (n = 27) and prolymphocytoid transformation of chronic lymphocytic leukemia (n = 14). Two groups of patients were individualized according to their clinical course: patients who died within one year of diagnosis (n = 14) and patients who had a prolonged survival (n = 23) without any treatment in some cases. The comparison between the 2 groups showed that they differed in age (p = 0.01) and anemia (p = 0.02). We also observed that the patients with p53 mutations had a worse clinical outcome. Taken together these data confirm that B-PLL should be regarded as a distinct form of chronic lymphoproliferative disorder and suggest the existence of two patterns of clinical evolution.

[Unusual presentation of nephroblastomatosis]. / Néphroblastomatose de présentation inhabituelle.

BACKGROUND: Nephrogenic rests generally constitute precursor lesions of Wilms' tumor. We report a case of right nephroblastomatosis with dysmorphic features. CASE REPORT: An enlargement of the right kidney was incidentally discovered in a 1-year-old girl with dysmorphic features but normal psychomotor development. Combined ultrasonography and computerized tomography (CT) scan showed right cortical nephroblastomatosis. Chemotherapy using actinomycin D and vincristin was successful; however, an hyperechogenic nodule was subsequently found, necessitating a right nephrectomy. CONCLUSION: The relationship between nephroblastomatosis and Wilms' tumor is discussed. This case report reminds us of the importance of a long-term follow-up including echography and CT scan in cases of nephroblastomatosis.

[Ultrasound abnormalities of the placenta during triploidy with pre-eclampsia in the 2nd trimester]. / Anomalies échographiques du placenta au cours d'une triploïdie avec pré-éclampsie au 2e trimestre.

A documented case of triploidism which developed to 20 weeks gestation underlines the importance of early ultrasonographic assessment of the trophoblast. Large placentas, especially when pre-eclampsia occurs, should lead to assay of beta-hCG and search for chromosome anomalies. Paternal genomic origin was suggested based on the large volume of the placenta.

Array-CGH Analysis Suggests Genetic Heterogeneity in Rhombencephalosynapsis.

Rhombencephalosynapsis is an uncommon, but increasingly recognized, cerebellar malformation defined as vermian agenesis with fusion of the hemispheres. The embryologic and genetic mechanisms involved are still unknown, and to date, no animal models are available. In the present study, we used Agilent oligonucleotide arrays in a large series of 57 affected patients to detect candidate genes. Four different unbalanced rearrangements were detected: a 16p11.2 deletion, a 14q12q21.2 deletion, an unbalanced translocation t(2p;10q), and a 16p13.11 microdeletion containing 2 candidate genes. These genes were further investigated by sequencing and in situ hybridization. This first microarray screening of a rhombencephalosynapsis series suggests that there may be heterogeneous genetic causes.

Specific language impairment as the prominent feature in a patient with a low-level trisomy 21 mosaicism.

BACKGROUND: The extent and severity of the disabilities is variable among individuals with Down syndrome, although generally characterized by a range of physical and intellectual conditions, including language impairment. Whether the language deficit is due to the intellectual disability (ID) or associated to the supernumerary or portion of chromosome 21 is still debated. METHODS: Karyotyping was performed on blood lymphocyte and skin fibroblasts. Fluorescence in situ hybridization analysis was performed on cultured lymphocytes and buccal smear cells. RESULTS: The trisomy 21 (T21) mosaicism was characterized by 0.7-10% of mosaic cells in the different tissues, in a 14-year-old girl presenting an intellectual development within the normal range and specific language impairment (SLI) as the only prominent feature. CONCLUSION: This case illustrates the wide range of phenotypical abnormalities possibly associated with T21 mosaicism. We propose that SLI is indeed a phenotypic trait specific to Down syndrome rather than subsequent to the ID most often associated to the syndrome.