Turner syndrome associated with Down syndrome: about a case / Síndrome Turner asociado a síndrome Down: a propósito de un caso

The coexistence of double aneuploidy of Down and Turner syndromes is rare; most cases have been due to double mitotic errors. The objective of the study was to report a case with monosomy of the X chromosome and trisomy of chromosome 21, in mosaic variety, highlighting the phenotypic effect that the presence of different chromosomal abnormalities can produce and compare with those reported in the literature. A 10-year-old Ecuadorian female, born to a multipregnant mother with 46 years at conception, is seen in consultation with a predominant clinical phenotype of Down syndrome, associated with menarche, presence of pubic and axillary villu, where a karyotype is verified 45 X[7]/47XX+ 21 [3]/46, X, der (X)(: p11.1-> q11.1)[1]/46,XX [1]. The present case is a double Turner-Down aneuploidy, with predominantly X monosomy cell line, who shows important mental retardation and some signs of puberal development not usually in Turner syndrome. These features highlight the clinical importance of doing a karyotype in mental retardation cases and searching low mosaics of another aneuploidies in atypical cases. Its complex chromosomal formula and support with molecular cytogenetics allowed diagnostic confirmation and genetic counseling.

La coexistencia de doble aneuploidía de los síndromes de Down y Turner es rara; la mayoría de los casos se han debido a dobles errores mitóticos. Reportar un caso con trisomía del cromosoma 21 y monosomía del cromosoma en X, en variedad mosaico, que curiosamente presenta un despertar puberal precoz y comparar con los reportados en la literatura. Paciente ecuatoriana de sexo femenino, de 10 años de edad, nacida de madre multigesta con 46 años a la concepción, que es vista en consulta con fenotipo clínico predominante de Síndrome Down, asociado a menarquia y telarquia, donde se constata un cariotipo. El presente caso es el primero informado de mosaicismo de doble aneuploidía de Turner-Down asociado con un despertar puberal precoz. Su fórmula cromosómica compleja y el apoyo con la citogenética molecular permitió la confirmación diagnostica y la asesoría genética.

Isocromosoma Xq en mosaico y microduplicación 17pl3. 3pl3. 2 en una paciente con síndrome de Turner y catarata congénita / Mosaic isochromosome Xq and microduplication 17p13. 3p13. 2 in a patient with Turner syndrome and congenital cataract

La combinación del síndrome de Turner con otros trastornos genéticos, como la catarata congénita, ha sido reportada. Sin embargo, su asociación con una forma de catarata nuclear congénita con herencia autosómica dominante y penetrancia incompleta no ha sido reportada previamente en la literatura. Tampoco existen reportes de su presentación junto con rearreglos en el cromosoma 17. A continuación, presentamos el excepcional caso de una paciente con una constelación de anomalías mayores y menores, diagnosticada con síndrome de Turner en mosaico por isocromosoma Xq, asociado a una microduplicación 17p13.3p13.2, quien además presenta catarata nuclear congénita bilateral de herencia autosómica dominante con penetrancia incompleta. Se realiza una revisión acerca del origen y la causa de estas alteraciones genéticas y una aproximación a la hipótesis de la patogénesis de la asociación de dos de estos trastornos genéticos en una misma paciente.

The combination of Turner syndrome with other genetic disorders such as congenital cataract has been reported, but its association with a congenital form with autosomal dominant inheritance and incomplete penetrance has not been previously reported in the literature. There are no reports on its presentations with rearrangements on chromosome 17. We report the exceptional case of a 20 months old girl with a constellation of major and minor anomalies, diagnosed with mosaic Turner syndrome by isochromosome Xq associated with a microduplication 17p13.3p13.2, who also had bilateral congenital nuclear cataract autosomal dominant with incomplete penetrance. We reviewed in the literature the origin and cause of these genetic alterations and we provided an approach to the hypothesis of the pathogenesis of the association of two of these genetic disorders in the same patient.

Isocromosoma 18q en mosaico: caso clínico / Mosaic Isochromosome 18q: case-report

Background: The Isochromosome 18q and chromosome 18 short arm deletion (18p-) constitute structural anomalies that are reported with certain frequency in the literature. However, the association of both abnormalities in a patient is very uncommon. Objective: Description of a clinical case of Isochromosome 18 with emphasys in the few phenotypic manifestations. Case-report: Female infant 18 months-old, with short stature, minor dysmorphic features and a slight psychomotor developmental delay, whose chromosomal study in peripheral blood showed a chromosomal mosaicism with two cell lines: chromosome 18 long arm isochromosome and deletion of chromosome 18 short arm. The chromosomal analysis of both parents did not show numerical neither morphological alterations. Discussion: This case illustrates the importance of requesting a karyotype in patients with small stature, dysmorphic features and/or malformations. The patient clinical features are compared with other similar cases described in the literature. The coexistence of both structural abnormalities (mosaicism) is extremely uncommon.

Introducción: El Isocromoma 18q y la deleción del brazo corto del cromosoma 18 (18p-), son anomalías estructurales que se reportan con cierta frecuencia en la literatura. Sin embargo, la asociación de ambas alteraciones en una misma paciente es muy infrecuente. Objetivo: Descripción de un caso clínico de Isocromosoma 18 con énfasis en la escasas manifestaciones fenotípicas. Caso Clínico: Lactante femenino de 18 meses de edad portador de talla baja, dismorfias menores y un leve retraso del desarrollo sicomotor, cuyo estudio cromosómico en sangre periférica mostró un mosaico compuesto por un isocromosoma del brazo largo del cromosoma 18 y otro cromosoma 18 con deleción del brazo p. El análisis cromosómico de ambos padres no mostró alteraciones numéricas ni morfológicas. Discusión: Este caso ilustra la importancia de solicitar un cariograma en pacientes con talla baja, dismorfias y/o malformaciones. Se describen las malformaciones encontradas y se compara con otros casos similares descritos en la literatura. La alteración estructural en mosaico reportada es sumamente infrecuente.

Coexistence of cytotypes and chromosomal mosaicism in Hoplias malabaricus (Characiformes, Erythrinidae)

Karyotypes of seventeen Hoplias malabaricus specimens, collected in the fish culture station of UNOPAR (University of Northern Paraná), were analyzed. The station is in the Claro River system in the Tibagi River basin. Two distinct and coexistent karyotype forms (cytotypes) were identified, comprising either 42 chromosomes (cytotype A) or 40 chromosomes (cytotype C), both presenting metacentric and submetacentric chromosomes. In two specimens, one male and one female, it was not possible to characterize a modal diploid number because different cell lines were observed, with a predominance of 2n=41 and 2n=42 chromosomes at a frequency of 38.24 percent and 41.12 percent, respectively. The karyotype with 2n=41 showed some putative monosomic and trisomic chromosomes, while the karyotype with 2n=42 showed 21 chromosomal pairs, similar to cytotype A. RAPD analysis showed that these two specimens have the same band pro file of cytotype A (Nei's genetic identity=92 percent), discarding a possible hybridization between both cytotypes and supporting the mosaicism hypothesis. These findings corroborate the isolation between cytotypes A and C.

Hemihypertrophy with hypomelanosis of Ito: A new syndrome combination

A female hemihypertrophy patient with hypomelanosis of Ito is presented as a rare case combining classical features of both the syndrome. Chromosomal profile has been based on longitudinal study of repeated lymphocyte cultures during 1984-1992. The propositus has exhibited chromosomal mosaicism both hypoploid (42+/-1) and hyperploid (48+/-2 chromosome) counts, but the major stem line presented 46XX chromosomes. Ring chromosome with simple and complex translocations with marker dots appear to be the major cytogenetic assemblage of this child to posses unequal left and right halves of the body. Each and every organ from toe to the head has grown up unequally and lately the patient had been exhibiting different dark and light shapes of melanin on the skin. We believe that the patient had inherited, through her male parent, "a few" mutated loci on some chromosomes so as to generate different cell lines within the developing child. All sibs and the mother showed normal karyotype with no apparent aberration.