Prenatal Genetics

Barcelona, Spain

Prenatal Genetics

Barcelona, Spain
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Morales C.,CIBER ISCIII | Cuatrecasas E.,Prenatal Genetics | Clusellas N.,CIBER ISCIII | Catala V.,Prenatal Genetics | And 7 more authors.
European Journal of Medical Genetics | Year: 2010

Trisomy 20 mosaicism is a common abnormality found in prenatal diagnosis. Its clinical significance remains unclear since approximately 90-93% of cases result in normal phenotype. Only 5 cases of non-mosaic trisomy 20 in amniotic fluid culture surviving beyond the first trimester have been reported. Moreover, trisomic cells are generally not detectable in blood and have only been reported in three cases. We present a case of non-mosaic trisomy 20 found in chorionic villi sample and amniotic fluid culture in a fetus with minor abnormalities not detected by ultrasound examination. Pathological examination of the fetus only revealed right pulmonary isomerism and camptodactily, and no major malformations were disclosed. Trisomic lineage was also detected in fetal blood, kidney, skin and brain tissue cultures. Molecular analysis revealed that the extra chromosome 20 was originated in paternal meiosis. To our knowledge, we report the first prenatal case of non-mosaic trisomy 20 of paternal origin that has been confirmed in several fetal tissues, including blood, in a fetus with minor malformations not detected prenatally. © 2010 Elsevier Masson SAS.

Plaja A.,General Laboratory Laboratoris dAnalisis | Plaja A.,Autonomous University of Barcelona | Lloveras E.,General Laboratory Laboratoris dAnalisis | Martinez-Bouzas C.,Hospital Universitario Cruces | And 9 more authors.
American Journal of Medical Genetics, Part A | Year: 2013

We present a clinical and molecular cytogenetic characterization of two new patients with a complex supernumerary marker consisting of the entire short arm of chromosome 18 with a chromosome 13/21 centromere. One patient is a girl with a nonsyndromic intellectual disability and the second is a prenatally diagnosed fetus. To our knowledge, these are the fourth and fifth such cases to be described in the literature, suggesting the existence of a possible recurring constitutional structural chromosome abnormality. © 2013 Wiley Periodicals, Inc.

Mayo S.,Hospital Universitario La Paz | Monfort S.,Hospital Universitario La Paz | Rosello M.,Hospital Universitario La Paz | Orellana C.,Hospital Universitario La Paz | And 5 more authors.
Cytogenetic and Genome Research | Year: 2011

Loss-of-function mutations of the MECP2 gene are the cause of most cases of Rett syndrome in females, a progressive neurodevelopmental disorder characterized by severe mental retardation, global regression, hand stereotypies, and microcephaly. On the other hand, gain of dosage of this gene causes the MECP2 duplication syndrome in males characterized by severe mental retardation, absence of speech development, infantile hypotonia, progressive spasticity, recurrent infections, and facial dysmorphism. Female carriers of a heterozygous duplication show a skewed X-inactivation pattern which is the most probable cause of the lack of clinical symptoms. In this paper, we describe a girl with a complex de novo copy number gain at Xq28 and non-skewed X-inactivation pattern that causes mental retardation and motor and language delay. This rearrangement implies triplication of the MECP2 and IRAK1 genes, but it does not span other proximal genes located in the common minimal region of patients affected by the MECP2 duplication syndrome. We conclude that the triplication leads to a severe phenotype due to random X-inactivation, while the preferential X chromosome inactivation in healthy carriers may be caused by a negative selection effect of the duplication on some proximal genes like ARD1A or HCFC1. Copyright © 2011 S. Karger AG.

Lloveras E.,Departament de Citogenetica | Canellas A.,Departament de Citogenetica | Cirigliano V.,LABCO Iberia | Catala V.,Prenatal Genetics | And 2 more authors.
Fetal Diagnosis and Therapy | Year: 2013

Characterization of marker chromosomes before the introduction of array CGH (aCGH) assays was only based on their banding patterns (G, C, and NOR staining) and fluorescent in situ hybridization techniques. The use of aCGH greatly improves the identification of marker chromosomes in some cases. We describe an atypical case of Pallister-Killian syndrome (PKS) detected at prenatal diagnosis with a very unusual cytogenetic presentation: a supernumerary ring chromosome including two copies of 12p. A similar anomaly described in a postnatal patient suggests ring chromosome as a possible cause of PKS. Extra ring chromosomes might be a more common etiology for PKS than previously thought, given the difficulty in their characterization before the advent of aCGH. © 2013 S. Karger AG, Basel.

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