Silver-Russell syndrome and Beckwith-Wiedemann syndrome phenotypes associated with 11p duplication in a single family.

Genomic imprinting is an epigenetic phenomenon resulting in differential expression of maternal and paternal alleles of a subset of genes. In the mouse, mutation of imprinted genes often results in contrasting phenotypes, depending on parental origin. The overgrowth-associated Beckwith-Wiedemann syndrome (BWS) and the growth restriction-associated Silver-Russell syndrome (SRS) have been linked with a variety of epigenetic and genetic defects affecting a cluster of imprinted genes at chromosome 11p15.5. Paternally derived and maternally derived 11p15.5 duplications represent infrequent findings in BWS and SRS, respectively. Here, we report a case in which a 6.5 Mb duplication of 11p15.4-pter resulted in SRS and BWS phenotypes in a child and her mother, respectively. Molecular analyses demonstrated that the duplication involved the maternal chromosome 11p15 in the child and the paternal chromosome 11p15 in the mother. This observation provides a direct demonstration that SRS and BWS represent specular images, both at the clinical and molecular levels.

Pregnancy outcome after genetic counselling for prenatal diagnosis of unexpected chromosomal anomaly.

OBJECTIVES: Couples undergoing invasive prenatal diagnosis (PD) are informed and concerned mainly about autosomal trisomies. However, unexpected chromosomal abnormalities (UCA) are a frequent finding at PD. We have analysed the psychological and practical consequences in the couples counselled in our centre because of the identification of foetal UCA at PD. METHODS: The study was carried out on a sample of 52 couples referred for genetic counselling in the period 1997-2000. The couples underwent a structured interview and two self-report instruments to measure anxiety and psychological characteristics. RESULTS: The couples have been divided into three groups: (1) low risk - without or with negligible risk, (2) mild risk - with mild risk or mild clinical phenotype and (3) sex chromosome anomaly. All couples received the diagnosis of chromosomal anomaly from the obstetrician without any other comments and were referred to our service for genetic counselling. Most couples felt fear (11/17 in the LR group, 5/7 in the MR group and 12/21 in the SCA group), while sadness was lower frequently felt by those parents-to-be in the LR group. CONCLUSIONS: Our study suggests that a specific counselling that mentions the possibility of UCA is mandatory before PD, and the cost-benefit estimate of PD should take into account the psychological implications of UCA detection.

Utilization of genetic counseling by parents of a child or fetus with congenital malformation in North-East Italy.

Congenital malformations (CM) affect 2-3% of all births, the cause of which, when known, is genetic in 80-90% of cases. A genetic consultation (GC) is indicated for the parents of a child affected by a CM. This study analyzes the parental utilization of genetic counseling (GCU) and its possible influencing factors after termination of pregnancy (TOP) because of fetal anomalies or after the birth of a child affected by a major malformation. The study concerns cases in North-East Italy where there is a CM registry and a center-satellite system for genetic counseling. The results of this analysis are also compared to other similar studies, which address the same topic. Between 1981 and 2000, 1,235 out of 14,888 GC were performed because of the presence of a CM in a child/fetus. In the same period, 4,933 births and 1,112 TOPs were registered. The overall GCU was 19%, with significant differences according to malformative phenotype, severity of the malformative condition, type of birth, and viability. Genetic counseling was performed significantly sooner following TOP than after the birth of a malformed child. GCU showed an unequal distribution according to the parents' place of residence, suggesting that easy and equal access to the genetic service was probably not well provided for. Our results suggest that genetic services should be integrated with related services, and that the public and physicians need a greater awareness of these services.