N Morichon

Publications (7)21.03 Total impact

• Article: Trinucleotide repeat contraction: a pitfall in prenatal diagnosis of myotonic dystrophy.

  J Amiel, V Raclin, J M Jouannic, N Morichon, H Hoffman-Radvanyi, M Dommergues, J Feingold, A Munnich, J P Bonnefont
  Journal of Medical Genetics 01/2002; 38(12):850-2. · 6.36 Impact Factor
• Article: [Contribution of genetics].

  S Lyonnet, N Morichon, M Dommergues, Y Dumez, M L Briard, M Vekemans, A Munnich
  Archives de Pédiatrie 02/1999; 6 Suppl 2:246s-248s. · 0.30 Impact Factor
• Article: Identification of novel L1CAM mutations using fluorescence-assisted mismatch analysis.

  P Saugier-Veber, C Martin, N Le Meur, S Lyonnet, A Munnich, A David, A Hénocq, D Héron, P Jonveaux, S Odent, S Manouvrier, A Moncla, N Morichon, N Philip, D Satge, M Tosi, T Frébourg
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  ABSTRACT: The L1CAM gene, which is located in Xq28 and codes for a neuronal cell adhesion molecule, is involved in three distinct conditions: HSAS (hydrocephalus-stenosis of the aqueduct of Sylvius), MASA (mental retardation, aphasia, shuffling gait, adductus thumbs), and SPG1 (spastic paraplegia). Molecular analysis of the L1CAM gene is labor-intensive because of the size of the coding region, which is fragmented in numerous exons, and because of the great allelic heterogeneity and distribution of the mutations. The FAMA (fluorescent assisted mismatch analysis) method combines the excellent sensitivity of the chemical cleavage method for scanning PCR fragments larger than 1 kb and the power of automated DNA sequencers. In order to optimize this method for L1CAM, we divided the gene into nine genomic fragments, each including three to four exons. These fragments were PCR-amplified using nine sets of primers containing additional rare universal sequences. A second-stage PCR, per formed with the two dye-labeled universal primers, allowed us to generate 1-kb-labeled fragments, which were then submitted to the chemical cleavage analysis. Among 12 French families with HSAS and/or MASA, we identified nine distinct L1CAM mutations, seven of which were novel, and an intronic variation. This study demonstrates that FAMA allows rapid and reliable detection of mutations in the L1CAM gene and thus represents one of the most appropriate methods to provide diagnosis for accurate genetic counseling in families with HSAS, MASA, or SPG1.
  Human Mutation 02/1998; 12(4):259-66. · 5.69 Impact Factor
• Article: Prezygotic origin of the isochromosome 12p in Pallister-Killian syndrome.

  V Cormier-Daire, M Le Merrer, N Gigarel, N Morichon, M Prieur, S Lyonnet, M Vekemans, A Munnich
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  ABSTRACT: Pallister-Killian syndrome is a rare disorder comprising multiple congenital anomalies, streaks of hypo(hyper)pigmentation, seizures, profound mental retardation, and the presence of an extra metacentric chromosome i(12)(p10), usually limited to skin fibroblasts. The mechanism and parental origin of the extra chromosome i(12)(p10) are unknown. Here, we present a girl with Pallister-Killian syndrome and the i(12)(p10) in 50% of cultured skin fibroblasts. Using microsatellite DNA markers of chromosome 12p, we detected 3 alleles--including 2 different alleles of maternal origin--in cultured skin fibroblasts, suggesting that the tetrasomy 12p is the result of a prezygotic event, with a nondisjunction event during maternal meiosis.
  American Journal of Medical Genetics 04/1997; 69(2):166-8.
• Article: Prenatal diagnosis in France.

  S Aymé, N Morichon, J Goujard, I Nisand
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  ABSTRACT: Prenatal diagnosis (PND) is very developed in France, especially in the area of ultrasound (US) screening. The activity is regulated by law, and laboratories have to be authorized to perform any type of prenatal biological test if the purpose is to diagnose fetal defects. There are 70 cytogenetics laboratories and 50 biochemistry laboratories performing serum marker screening, about half of them being private. PND of chromosomal anomalies is offered to women over 37 years of age, to women who already had a child with a chromosomal anomaly, in case of abnormal US findings, if one of the parents has a balanced chromosomal anomaly and if the risk of chromosomal anomaly is higher than 1:250 according to the serum markers. Half of the trisomy 21 cases are now detected prenatally and pregnancies terminated. Fetal cell sampling is performed by amniocentesis in 70% of cases, by chorionic villus sampling in 7% of cases and by fetal blood sampling in 23% of cases. There are no professional guidelines and no quality assessment networks for any of the techniques in use. PND is regulated by two major laws: the Law on Abortion (1975) and the Law on Bioethics (1994).
  European Journal of HumanGenetics 02/1997; 5 Suppl 1:26-31. · 4.40 Impact Factor
• Article: Chromosomal prenatal diagnosis: study of 936 cases of intrauterine abnormalities after ultrasound assessment.

  P Eydoux, A Choiset, N Le Porrier, F Thépot, S Szpiro-Tapia, J Alliet, S Ramond, J F Viel, E Gautier, N Morichon
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  ABSTRACT: Nine hundred and thirty-six prenatal chromosomal analyses were performed by four cytogenetic centres after ultrasound diagnosis of fetal abnormalities, amniotic fluid disorders, fetal growth retardation, and fetal or placental abnormalities. During the same period, 6515 fetal karyotypes were analysed because of maternal age. Frequencies of chromosomal aberrations in each case were respectively 4.4, 6.7 and 15.8 per cent, compared with 3.18 per cent when the fetal karyotype was performed because of maternal age. High rates of chromosomal aberrations are observed in cases of cervical hygroma, limb abnormalities, omphaloceles, duodenal stenosis, hydrocephalus, and facial abnormalities. In the case of polymalformations, this rate was 29.2 per cent. When malformations were seen together with an amniotic fluid disorder or growth retardation, 21.5 per cent chromosomal aberrations were observed. This frequency was 10.4 per cent when growth retardation was associated with an amniotic fluid disorder. Trisomy 13, 18, 21 and monosomy X accounted for 4/5 of all abnormalities in which we observed a high rate of triploidies (4.9 per cent) and balanced (3.3 per cent) or unbalanced (9.8 per cent) non-Robertsonian structural abnormalities. Sonographic ascertainment of these aberrations and prenatal characteristics of major anomalies are discussed.
  Prenatal Diagnosis 05/1989; 9(4):255-69. · 2.11 Impact Factor
• Article: Prenatal diagnosis and molecular characterization of an interstitial 1q24.2q25.2 deletion.

  M Chaabouni, J Martinovic, D Sanlaville, T Attié-Bittach, S Caillat, C Turleau, M Vekemans, N Morichon
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  ABSTRACT: We report on the observation of an interstitial deletion of the long arm of chromosome 1 diagnosed prenatally in a 28 weeks gestation fetus by standard karyotype. Amniocentesis was performed because of an increased Down syndrome maternal serum screening and ultrasonographic abnormalities. Fetus autopsy showed an intrauterine growth retardation, dysmorphic features and limbs abnormalities. Using fluorescent in situ hybridization technique (FISH), we characterized the deletion boundaries corresponding to the bacterial artificial chromosomes (BAC) RP11-193J5 and RP11-162L13. Molecular studies identified the deletion of paternal origin. Therefore the karyotype was interpreted as 46,XY,del(1)(q24.2q25.2). This is the smallest deletion of the long arm of chromosome 1 reported prenatally and characterized at the molecular level. Its phenotype is compared to other similar cases described in the literature.
  European Journal of Medical Genetics 49(6):487-93. · 2.18 Impact Factor