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 37.2% (151/406) of included patients, a pregnancy was already ongoing. The mean gestational age at first contact was 13.6 weeks (SD 5.5 weeks). The main counselling issues were previous pregnancy with abortive outcome (ICD O00-O08) 23.9% (97/406), chromosomal abnormalities (ICD Q90-Q99) 16.7% (68/406) and metabolic disorders (ICD E70-E90) 9.9% (40/406). As a result of prenatal genetic counselling, invasive prenatal diagnostic procedures were performed in 11.3% (46/406) of all patients. CONCLUSION: Patients are often referred to prenatal genetic counselling when prenatal diagnosis of a familial genetic condition is no longer feasible, preventive measures are limited and alternative reproductive options have become impossible. Healthcare providers are challenged to improve services so prenatal genetic counselling can take place before conception.

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 q26.1-ter on chromosome 15 occurring as a de novo event associated with CDH. A detailed review of the literature provides further evidence of a functional association between deletions within the chromosomal region 15q24-ter and the development of CDH. CONCLUSIONS: The obtained data argue that detection of such a deletion in the region 15q24-ter associated with CDH likely predicts a poor prognosis. This report highlights the importance of giving special diagnostic attention to the chromosomal region 15q24-ter when prenatal ultrasound examination provides evidence of a CDH and warrants further research to identify genetic elements within the chromosomal region 15q24-ter related to the development of diaphragmatic hernia.

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. This report describes the fourth case of a tetrasomy 9p associated with Dandy-Walker malformation. CONCLUSIONS: This case, together with the three previously reported cases of an association with a tetrasomy 9p, indicate that this chromosomal aberration should be looked for when Dandy-Walker malformation is detected via prenatal ultrasonography.

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 9q22.1-->q33. The patient (female, age 17 years) presented with growth retardation, microcephaly, facial dysmorphia, oesophageal atresia, aortic stenosis, ventricular septal defect, atrial septal defect II, hypothyroidism, and learning disability, but no pyloric stenosis. A review of all cases of partial trisomy 9q reported in the literature demonstrates that learning disability is a characteristic feature of this group of chromosomal aberrations. However, there are cases of duplications of the same chromosome 9 material, with and without pyloric stenosis. This study provides new information for future genetic counselling, especially in cases of prenatal diagnosis of partial trisomy 9q.