QF-PCR as a stand-alone test for prenatal samples: the first 2 years' experience in the London region.

OBJECTIVE: To analyse the results of the first 2 years of a QF-PCR stand-alone testing strategy for the prenatal diagnosis of aneuploidy in the London region and to determine the advantages and disadvantages of this policy. METHODS: A review of the results of 9737 prenatal samples received for exclusion of chromosome abnormalities. All samples were subjected to QF-PCR testing for common aneuploidies but only samples fulfilling specific criteria subsequently had a full karyotype analysis. RESULTS: Of the 9737 samples received, 10.3% had a chromosome abnormality detected by QF-PCR testing. Of the 7284 samples received with no indication for karyotype analysis, 25 (0.3%) received a normal QF-PCR result but subsequently had an abnormal karyotype detected either prenatally as a privately funded test or postnatally. Of these samples, without subsequent abnormal ultrasound findings, five had a chromosome abnormality associated with a poor prognosis, representing 0.069% of samples referred for Down syndrome testing. CONCLUSION: While back-up karyotyping is required for some samples, using QF-PCR as a stand-alone prenatal test for pregnancies without ultrasound abnormalities reduces costs, provides rapid delivery of results, and avoids ambiguous and uncertain karyotype results, reducing parental anxiety.

Preoperative Practice Paired With Instructor Feedback May Not Improve Obstetrics-Gynecology Residents' Operative Performance.

BACKGROUND: There is evidence that preoperative practice prior to surgery can improve trainee performance, but the optimal approach has not been studied. OBJECTIVE: We sought to determine if preoperative practice by surgical trainees paired with instructor feedback improved surgical technique, compared to preoperative practice or feedback alone. METHODS: We conducted a randomized controlled trial of obstetrics-gynecology trainees, stratified on a simulator-assessed surgical skill. Participants were randomized to preoperative practice on a simulator with instructor feedback (PPF), preoperative practice alone (PP), or feedback alone (F). Trainees then completed a laparoscopic salpingectomy, and the operative performance was evaluated using an assessment tool. RESULTS: A total of 18 residents were randomized and completed the study, 6 in each arm. The mean baseline score on the simulator was comparable in each group (67% for PPF, 68% for PP, and 70% for F). While the median score on the assessment tool for laparoscopic salpingectomy in the PPF group was the highest, there was no statistically significant difference in assessment scores for the PPF group (32.75; range, 15-36) compared to the PP group (14.5; range, 10-34) and the F group (21.25; range, 10.5-32). The interrater correlation between the video reviewers was 0.87 (95% confidence interval 0.70-0.95) using the intraclass correlation coefficient. CONCLUSIONS: This study suggests that a surgical preoperative practice with instructor feedback may not improve operative technique compared to either preoperative practice or feedback alone.

Constitutional deletion of chromosome 20q in two patients affected with albright hereditary osteodystrophy.

Albright hereditary osteodystrophy (AHO) results from heterozygous inactivation of G(s)alpha, encoded by the GNAS1 locus on the distal long arm of chromosome 20. This autosomal dominant condition is characterized by short stature, obesity, shortening of the metacarpals and metatarsals, and variable mental retardation and may also include end-organ resistance to multiple hormones. Small insertions and deletions or point mutations of GNAS1 are found in approximately 80% of patients with AHO. The remainder may be accounted for by larger genomic rearrangements, but none have been reported to date. We now describe two patients with constitutional 20q deletions and features of AHO. Such deletions are rare in the published literature and have not previously been associated with AHO. Molecular genetic analysis confirmed complete deletion of GNAS1 in both patients. Parental origin could be determined in both cases and provides further support for the parent-of-origin effect on the biochemical status of patients with AHO.