Prenatal sonographic features of trisomy 1q

Congenital high airway obstruction syndrome (CHAOS) associated with cervical myelomeningocele

Congenital high airway obstruction syndrome (CHAOS) is a rare and potentially fatal entity resulting from complete or near complete developmental airway obstruction. Although most reported cases of CHAOS are sporadic, the condition may also be associated with certain syndromes and a variety of cervical masses. Meningocele and myelomeningocele have not yet been reported in association with CHAOS. We describe the typical constellation of sonographic findings in a case of early diagnosis of CHAOS associated with cervical myelomeningocele. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:507-510, 2017.

Prenatal diagnosis of proximal partial trisomy 1q confirmed by comparative genomic hybridization array: molecular cytogenetic analysis, fetal pathology and review of the literature

BACKGROUND

Partial trisomy of the long arm of chromosome 1 (1q) is an exceptionally rare chromosomal abnormality and most of the prenatally diagnosed cases are associated with either complete (q11-qter) or large (q21-qter) duplications with pre- or perinatal demise of all reported cases. The most common sonographic findings associated with this karyotype abnormality include ventriculomegaly, increased nuchal translucency or nuchal fold, renal and cardiac abnormalities, craniofacial dysmorphism, and limb deformities. However, there is a wide spectrum of clinical manifestations due to the great variability in the extent of the duplication size and the possible contribution of additional genetic rearrangements in the final phenotype.

CASE REPORT

We report on a female fetus with sole partial trisomy 1q presenting with multiple structural malformations in the second trimester scan. Standard karyotyping demonstrated a large duplication on the proximal end of chromosome 1 [46,XX,dup(1)(pter→q31::q31→q12::q31→qter)] and further application of comparative genomic hybridization array confirmed the diagnosis and offered a precise characterization of the genetic defect.

CONCLUSION

A fetus with nonmosaic partial trisomy 1q that was prenatally diagnosed upon multiple abnormal ultrasound findings is presented. A detailed review of the currently available literature on the prenatal diagnostic approach of partial trisomy 1q in terms of fetal sonographic assessment and molecular cytogenetic investigation is also provided. The use of novel molecular techniques such comparative genomic hybridization array could shed further light on the correlation between the genes identified in the chromosomal region of interest and the resultant phenotype.

A rare case of a mosaic unbalanced translocation after chorionic villous sampling

BACKGROUND

Most of the literature suggests that unbalanced chromosomal translocations may lead to poor obstetrical outcomes. We present a case of an unbalanced translocation resulting in trisomy 1q and partial monosomy 20p identified on chorionic villous sampling (CVS).

METHOD

Case report with expert-derived clinical management and guidance.

RESULTS

After the abnormal CVS result, a subsequent amniocentesis revealed a normal 46,XX fetal karyotype. Detailed second trimester ultrasound of the fetus revealed no gross structural abnormalities. The CVS karyotype results were attributed to confined placental mosaicism (CPM) of the unbalanced translocation. The infant is 18 months old and has normal phenotype and karyotype.

CONCLUSION

We recommend that if CPM with an unbalanced translocation is diagnosed on CVS, parental karyotype and an amniocentesis should be offered in conjunction with genetic counseling. In rare instances, such as this one, an unbalanced translocation may have a favorable outcome.

Increased nuchal translucency in euploid fetuses--what should we be telling the parents?

Nuchal translucency (NT) measurement between 11 and 14 weeks' gestation is an undisputed marker for aneuploidies. When conventional karyotyping is normal, enlarged NT is a strong marker for adverse pregnancy outcome, associated with miscarriage, intrauterine death, congenital heart defects, and numerous other structural defects and genetic syndromes. The risk of adverse outcome is proportional to the degree of NT enlargement. Although the majority of structural anomalies are amenable to ultrasound detection, unspecified genetic syndromes involving developmental delay may only emerge after birth. Concern over these prenatally undetectable conditions is a heavy burden for parents. However, following detection of enlarged NT the majority of babies with normal detailed ultrasound examination and echocardiography will have an uneventful outcome with no increased risk for developmental delay when compared to the general population. Counseling should emphasize this to help parents restore hope in normal pregnancy outcome and infant development.

Mosaic trisomy 1q: The longest surviving case

We present the longest known surviving case of a male infant with a mosaic complete trisomy 1q. Born at 39 weeks of gestation with respiratory distress, his weight was 3,330 g (25th centile); he had micrognathia, a posterior cleft of palate, abnormal ears and left thumb, syndactyly, and an absent corpus callosum. Initial blood karyotype was normal (46,XY). He died at age 5 months. Autopsy suggested aspiration as the primary cause of death and confirmed the antemortem findings of an absent corpus callosum and atrial septal defect. It also identified some central nervous system, cardiac, gastrointestinal, and lung anomalies not previously recognized. Cytogenetic analysis of skin fibroblasts obtained at autopsy showed a de novo unbalanced translocation between chromosomes 1 and 22: 46,XY,+1,der(1;22)(q10;q10)[25]/46,XY[65] in the cells examined. The previously reported cases had a similar phenotype with birth weight above the 50th centile for gestational age, small mouth, micrognathia, abnormal ears, abnormal fingers, microphthalmia, and hydrocephalus. The present case and a review of the literature delineates the phenotype in trisomy 1q, and reinforces the critical importance of effective communication between specialists, and obtaining permission for autopsy and skin biopsy, in the pursuit of a diagnosis.

Ultrasound manifestations of unusual trisomies-excluding trisomy 13, 18, and 21: a literature review

Trisomy is the most commonly identified chromosome abnormality, occurring in at least 4% of all clinically recognized pregnancies (1). Most of the trisomies are associated with a single additional chromosome, although 2 other types of trisomic conceptions are occasionally observed, those with 2 additional chromosomes or double trisomy and those with both a normal and trisomic cell line or mosaic trisomies. The adverse effects of trisomy on the phenotype are well established. In this review article, we consider the prevalence of the unusual trisomies (excluding 13, 18, and 21) and present a review of their ultrasound findings.