ABSTRACT
Trisomy 11 mosaicism is clinically rare, for which making diagnostic and treatment decisions can be challenging. In this study, we used noninvasive prenatal testing, chromosome karyotype analysis, chromosome microarray analysis, copy number variation sequencing and fluorescence in situ hybridization for detecting trisomy 11 mosaicism in two cases and provided them with genetic counseling. In one of the cases, the fetus with confined placental mosaicism trisomy 11 presented with severe growth restriction and a placental mosaic level of 44%, and pregnancy was terminated at 25+3 weeks of gestation. In the other case with true low-level fetal mosaicism of trisomy 11, the pregnancy continued after exclusion of the possibility of uniparental disomy and structural abnormalities and careful prenatal counseling. The newborn was followed up for more than one year, and no abnormality was found. Noninvasive prenatal testing is capable of detecting chromosomal mosaicism but may cause missed diagnosis of true fetal mosaicism. For cases with positive noninvasive prenatal testing but a normal karyotype of the fetus, care should be taken in prenatal counseling and pregnancy management.
Subject(s)
Female , Humans , Infant, Newborn , Pregnancy , Chromosome Disorders/diagnosis , DNA Copy Number Variations , Genetic Testing , In Situ Hybridization, Fluorescence , Mosaicism , Placenta , Prenatal Diagnosis , Trisomy/geneticsABSTRACT
Se define como restricción del crecimiento intrauterino (RCIU) a la alteración en el crecimiento fetal que determina un peso por debajo de la percentila 10 para la edad gestacional. Las causas genéticas de RCIU pueden dividirse en: cromosómicas, alteraciones de la epigenética o impronta y síndromes génicos. Se presenta el caso de una paciente con RCIU referida por sospecha de displasia ósea, en la que se descartó disfunción vascular placentaria por ultrasonido prenatal, infecciones, patología materna y displasias óseas por estudio radiológico normal. Se realizó cariotipo en el cordón umbilical y en tres diferentes sitios de la placenta por la posibilidad de un mosaico placentario, obteniéndose un resultado normal. Al nacimiento presentó peso y talla por debajo de la percentila 3, cráneo dolicocéfalo con frontal prominente, fontanela anterior amplia, cara pequeña, triangular con mentón en punta y clinodactilia bilateral. A los dos meses de edad se observó asimetría de extremidades inferiores y se refirió reflujo gastroesofágico. Con base en los criterios clínicos y resultados obtenidos se realizó el diagnóstico de síndrome de Silver-Russell.
Intrauterine growth restriction (IUGR) is an alteration in fetal development in which the fetal weight is below the 10th percentile for gestational age. The genetic causes of IUGR can be classified as: chromosomal, epigenetic and other imprinting disorders and monogenic syndromes. We report a patient with IUGR referred to our hospital with the prenatal diagnosis of achondroplasia. Vascular malfunction of the placentae, maternal pathology, and skeletal dysplasia were discarded. A karyotype in umbilical cord and in three different placental spots was performed, with a normal result in all of them, ruling out placentae mosaicism. At birth, the weight and height were below the 3th percentile. Physical examination showed: dolicocephaly, frontal prominence, large fontanels, small and triangular face, pointed chin and incurved bilateral fifth fingers. Two months later a lower limb asymmetry was noticed and gastroesophageal reflux was referred. With these clinical abnormalities and the studies performed the diagnosis of Silver-Russell syndrome was established.
ABSTRACT
The present report describes a case that showed a normal fetal karyotype in an antenatal genetic study but an abnormal placental karyotype of 46,XX,r(15) on postnatal examination. The pregnancy was complicated by fetal nuchal translucency in the first trimester and intrauterine growth restriction in the second and third trimesters. A 1780 gm female baby was born after 40 weeks of gestation, but died of respiratory distress and sepsis on the 10th day of life. Our case was unique in that the placental chromosomal aberration was a structural abnormality instead of a numerical aberration that is seen in most reported cases of confined placental mosaicism.