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Screening for fragile X syndrome could potentially reduce the incidence of mental retardation. Fragile X syndrome is a common inheritable cause of mental retardation. The odds of retardation relate to the number of repeating segments within the gene. The risk of retardation is low when a person has the premutation, which occurs when there are 50 to 200 repeats. Above 200 repeats, which is considered full mutation, the risk is high. Testing was offered to 515 people with at least a 12.5% likelihood of carrying the premutation or full mutation. Sixty-six people had the full mutation and 163 had the premutation. All 21 pregnant carriers had a chorionic villus biopsy, which identified nine embryos with the full mutation and three with the premutation. All pregnancies with the full mutation were terminated.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ajog.2006.11.040 Byline: Yrtti Valinen (1), Katrin Rapakko (2), Hannaleena Kokkonen (2), Paivi Laitinen (3), Aydin Tekay (1), Tarja Ahola (4), Markku Ryynanen (1) Keywords: Down syndrome; first-trimester trisomy screening; maternal serum screening; prenatal diagnosis Abstract: The purpose of this study was to compare the efficacy of both separate and combined maternal serum testing and fetal nuchal translucency measurement in the first trimester screening for Down syndrome in northern Finland. Author Affiliation: (1) Department of Obstetrics and Gynecology, Department of Oulu University Hospital, Finland (2) Department of Clinical Genetics, Department of Oulu University Hospital, Finland (3) Department of Laboratory, Department of Oulu University Hospital, Finland (4) Department of PerkinElmer, Wallac, Turku, Finland. Article History: Received 5 July 2006; Revised 3 October 2006; Accepted 30 November 2006 Article Note: (footnote) Cite this article as: Valinen Y, Rapakko K, Kokkonen H, et al. Clinical first-trimester routine screening for Down syndrome in singleton pregnancies in northern Finland. Am J Obstet Gynecol 2007;196;278.e1-278.e5.

Approximately one in five subjects in Finland carries some gene defect associated with 30 diseases belonging to the Finnish disease heritage, and about one in 500 children born is affected. Almost all carriers, women and men, are unaware of their condition. Recent advances in molecular medicine have offered the possibility of population‐based carrier screening for recessive disorders. We studied acceptance and attitudes to antenatal screening for aspartylglucosaminuria (AGU) and infantile neuronal ceroid lipofuscinosis (INCL).

The mutation for adult polycystic kidney disease (APKD) has previously been localised to chromosome 16 by the demonstration of genetic linkage with the loci for the alpha-chain of haemoglobin and phosphoglycolate phosphatase. These studies were carried out, however, on only nine families so that the possibility remained that mutations at other genetic loci might produce the disease. Such genetic heterogeneity of linkage would invalidate the general use of chromosome 16 markers for the purposes of detection of the disease, and complicate the characterisation of APKD at the molecular level. Therefore further families were studied to address this question. A total of 28 northern European pedigrees were analysed, all apparently unrelated, and with origins in England, Scotland, Holland and eastern Finland. No evidence was found to suggest heterogeneity of genetic linkage between alpha-globin and the APKD locus in this population.