Timing of referral for prenatal genetic counselling.

Objective: To evaluate the timing of referrals for prenatal genetic counselling.

Method: The data of 406 consecutive patients referred because of a family history of genetic disease or a suspected risk factor for genetic disease other than an unfavourable first trimester screening outcome were retrospectively analysed.

Results: In 37.

Association of deletions of the chromosomal region 15q24-ter and diaphragmatic hernia: a new case and discussion of the literature.

Objective: To provide new insights into how chromosomal aberrations affect fetal development, as well as for the counseling of parents in comparable situations, it is important to characterize and report the genotypes of fetuses with clinical anomalies.

Methods: Molecular cytogenetic analyses in a fetus with congenital diaphragmatic hernia (CDH).

Results: This report describes the first case of a deletion of the region q26.

Prenatal diagnosis of tetrasomy 9p with Dandy-Walker malformation.

Objectives: To add to the knowledge of chromosomal abnormalities associated with Dandy-Walker malformation.

Methods: Molecular cytogenetic analyses of a chorionic villus sampling and of an amniocentesis of a fetus with Dandy-Walker malformation and abnormal somatic development.

Results: All cells examined showed a 47, XY, +idic(9p)(pter-->q12::q12-->pter) de novo karyotype.

Patient with partial trisomy 9q and learning disability but no pyloric stenosis.

Partial trisomy of the long arm of chromosome 9 represents a very rare and heterogeneous group of chromosomal aberrations. Associated clinical features include learning disability and pyloric stenosis. We present the first patient to be reported with a duplication of the chromosome region 9q22.

Prenatal diagnosis of a supernumerary aberrant chromosome 9.

For counselling of parents, as well as to basically understand how chromosome aneuploidies affect embryonic or fetal development, it is of great importance to analyse and collect genotypes of fetuses with clinical anomalies. This report describes the first prenatal diagnosis of a supernumerary chromosome 9 with deletion of the chromosome region 9q34. Ultrasound examination in the 13th week of gestation detected increased nuchal translucency of 6.

Prenatal diagnosis of a de novo inversion of chromosome (2)(p21q11).

Prenatal diagnosis of "apparently balanced" chromosomal rearrangements, if not inherited from a parent, are problematic for genetic counsellors and families. Although the parents need to be informed about the increased risk of multiple congenital anomalies, the anomalies that the fetus is at risk can not be discussed unless a similar breakpoint and accompanying phenotype have been reported in the literature. In the reported case prenatal ultrasound examination revealed a massive hydrocephalus internus and IUGR.

Prenatal diagnosis of a de novo supernumerary marker derived from chromosome 16.

Marker chromosomes are supernumerary chromosomes of unknown origin and are seldom found in prenatal diagnosis. Application of fluorescent in situ hybridization (FISH) allows the identification of the chromosomal origin of markers. Estimation of the risk of an abnormal phenotype outcome can be enabled by collecting data on phenotypes associated with markers of the same chromosomal origin.