Clinical experience with single-nucleotide polymorphism-based non-invasive prenatal screening for 22q11.2 deletion syndrome.

OBJECTIVES: To evaluate the performance of a single-nucleotide polymorphism (SNP)-based non-invasive prenatal test (NIPT) for the detection of fetal 22q11.2 deletion syndrome in clinical practice, assess clinical follow-up and review patient choices for women with high-risk results. METHODS: In this study, 21 948 samples were submitted for screening for 22q11.2 deletion syndrome using a SNP-based NIPT and subsequently evaluated. Follow-up was conducted for all cases with a high-risk result. RESULTS: Ninety-five cases were reported as high risk for fetal 22q11.2 deletion. Diagnostic testing results were available for 61 (64.2%) cases, which confirmed 11 (18.0%) true positives and identified 50 (82.0%) false positives, resulting in a positive predictive value (PPV) of 18.0%. Information regarding invasive testing was available for 84 (88.4%) high-risk cases: 57.1% (48/84) had invasive testing and 42.9% (36/84) did not. Ultrasound anomalies were present in 81.8% of true-positive and 18.0% of false-positive cases. Two additional cases were high risk for a maternal 22q11.2 deletion; one was confirmed by diagnostic testing and one had a positive family history. There were three pregnancy terminations related to screening results of 22q11.2 deletion, two of which were confirmed as true positive by invasive testing. CONCLUSIONS: Clinical experience with this SNP-based non-invasive screening test for 22q11.2 deletion syndrome indicates that these deletions have a frequency of approximately 1 in 1000 in the referral population with most identifiable through this test. Use of this screening method requires the availability of counseling and other management resources for high-risk pregnancies.

Pregnancy associated plasma protein-A2: a novel biomarker for Down syndrome.

INTRODUCTION: In an effort to improve prenatal screening for Trisomy 21, we evaluated pregnancy associated plasma protein-A2 (PAPP-A2) as a potential novel second trimester biomarker for Trisomy 21. METHODS: Trisomy 21 and normal control mid-trimester placental samples were subjected to quantitative rt PCR analysis of seven genes we had previously found to be differentially expressed in Trisomy 21 placentae. The localization and differential expression of PAPP-A2 in second trimester placentae from normal and Trisomy 21 pregnancies was determined by immunohistochemistry. PAPP-A2 maternal serum protein levels in ten Trisomy 21 and ten diploid pregnancies were compared by Western blotting. Maternal serum PAPP-A2 levels were measured in 30 Down syndrome cases and 142 normal controls, using ELISA. Regression analysis was used to determine the correlation of PAPP-A2 with other existing markers of Trisomy 21. RESULTS: PAPP-A2 (aka PLAC 3) mRNA and protein expression were both increased in Down syndrome placentae as compared to diploid placentae. PAPP-A2 was also increased in maternal serum from Down syndrome pregnancies as compared to diploid pregnancies. PAPP-A2 expression correlated weakly with established markers. DISCUSSION: This work takes advantage of our previously performed systematic approach to the discovery of novel maternal serum biomarkers for Trisomy 21, using cDNA microarray analysis. Beginning with the validation of the microarray results, we have tracked PAPP-A2 overexpression in Down syndrome from placental mRNA to maternal serum protein. CONCLUSION: PAPP-A2 could serve as an additional maternal serum marker in prenatal screening for Trisomy 21.

Cognitive and Antipsychotic Medication Use in Monoallelic GBA-Related Parkinson Disease.

Mutations in glucosidase, beta, acid (GBA) are associated with cognitive impairment in Parkinson disease (PD) as well as dementia with Lewy bodies. For both of these diseases, dementia and hallucinations are typically treated with cholinesterase inhibitors and antipsychotics. However, in some lysosomal storage disorders certain antipsychotic medications are poorly tolerated. This study examined cholinesterase inhibitor and antipsychotic use in monoallelic GBA-related PD to explore potential pharmacogenetic relationships. Monoallelic GBA mutation carriers with PD (GBA-PD) with at least two clinic visits (n = 34) were matched for age-of-onset and gender to GBA and leucine-rich repeat kinase 2 (LRRK2) mutation negative idiopathic PD subjects (IPD) (n = 60). Information regarding cholinesterase inhibitor and antipsychotic use as well as impaired cognition (UPDRS Mentation >1) and hallucinations (UPDRS Thought Disorder >1) were obtained. GBA-PD more frequently reported hallucinations (HR = 5.0; p = 0.01) and they were more likely to have cognitive impairment but this was not statistically significant (HR 2.2, p = 0.07). Antipsychotic use was not significantly different between GBA-PD and IPD (HR = 1.9; p = 0.28), but GBA-PD were more likely to have sustained cholinesterase inhibitor use (HR = 3.1; p = 0.008), even after adjustment for cognition and hallucinations. Consistent with reports of worse cognition, GBA-PD patients are more likely to use cholinesterase inhibitors compared to IPD. While there was no difference in antipsychotic use between IPD and GBA-PD, persistent use of quetiapine in GBA-PD suggests that it is tolerated and that a significant interaction is unlikely. Further prospective study in larger samples with more extensive cognitive assessment is warranted to better understand pharmacogenetic relationships in GBA-PD.

ACMG statement on noninvasive prenatal screening for fetal aneuploidy.

Noninvasive assessment of the fetal genome is now possible using next-generation sequencing technologies. The isolation of fetal DNA fragments from maternal circulation in sufficient quantity and sizes, together with proprietary bioinformatics tools, now allows patients the option of noninvasive fetal aneuploidy screening. However, obstetric care providers must become familiar with the advantages and disadvantages of the utilization of this approach as analysis of cell-free fetal DNA moves into clinical practice. Once informed, clinicians can provide efficient pretest and posttest counseling with the goal of avoiding patient harm. It is in the public's best interest that test results contain key elements and that laboratories adhere to established quality control and proficiency testing standards. The analysis of cell-free fetal DNA in maternal circulation for fetal aneuploidy screening is likely the first of major steps toward the eventual application of whole fetal genome/whole fetal exome sequencing.

Transcranial sonography and functional imaging in glucocerebrosidase mutation Parkinson disease.

BACKGROUND: Heterozygous glucocerebrosidase (GBA) mutations are the leading genetic risk factor for Parkinson disease, yet imaging correlates, particularly transcranial sonography, have not been extensively described. METHODS: To determine whether GBA mutation heterozygotes with Parkinson disease demonstrate hyperechogenicity of the substantia nigra, transcranial sonography was performed in Ashkenazi Jewish Parkinson disease subjects, tested for the eight most common Gaucher disease mutations and the LRRK2 G2019S mutation, and in controls. [(18)F]-fluorodeoxyglucose or [(18)F]-fluorodopa positron emission tomography is also reported from a subset of Parkinson disease subjects with heterozygous GBA mutations. RESULTS: Parkinson disease subjects with heterozygous GBA mutations (n = 23) had a greater median maximal area of substantia nigral echogenicity compared to controls (n = 34, aSNmax = 0.30 vs. 0.18, p = 0.007). There was no difference in median maximal area of nigral echogenicity between Parkinson disease groups defined by GBA and LRRK2 genotype: GBA heterozygotes; GBA homozygotes/compound heterozygotes (n = 4, aSNmax = 0.27); subjects without LRRK2 or GBA mutations (n = 32, aSNmax = 0.27); LRRK2 heterozygotes/homozygotes without GBA mutations (n = 27, aSNmax = 0.28); and GBA heterozygotes/LRRK2 heterozygotes (n = 4, aSNmax = 0.32, overall p = 0.63). In secondary analyses among Parkinson disease subjects with GBA mutations, maximal area of nigral echogenicity did not differ based on GBA mutation severity or mutation number. [(18)F]-fluorodeoxyglucose (n = 3) and [(18)F]-fluorodopa (n = 2) positron emission tomography in Parkinson disease subjects with heterozygous GBA mutations was consistent with findings in idiopathic Parkinson disease. CONCLUSIONS: Both transcranial sonography and positron emission tomography are abnormal in GBA mutation associated Parkinson disease, similar to other Parkinson disease subjects.

Relationship between salivary IgA secretion and upper respiratory tract infection following a 160-km race.

AIM: The relationship between salivary IgA secretion rate and upper respiratory tract infection (URTI) was studied in 155 ultramarathoners (126 males, 29 females, mean age 46.5+/-0.7 y) who had qualified to run the 160-km 2003 Western States Endurance Run. METHODS: Subjects provided saliva samples during registration, held the morning before the race, and within 5-10 minutes postrace (mean race time, 26.2+/-0.3 h). Unstimulated saliva was collected by expectoration for 4 minutes into 15-mL plastic, sterilized vials. Runners finishing the race and providing pre- and postrace saliva samples (n=106) turned in a health log specifying URTI episodes and severity of symptoms for the 2-week period following the race. RESULTS: The total volume of saliva that the runners was able to expectorate during sample collection decreased 51% postrace compared to prerace values (P<0.001). Saliva protein concentration increased 20% (P<0.001) while the saliva protein IgA concentration decreased 10% (P<0.05). Salivary IgA secretion rate decreased 46% when comparing pre- to postrace values (P<0.001). Twenty-four percent of the runners finishing the race and providing salivary samples reported an URTI episode lasting 2 days or longer during the 2-week period following the race (mean number of days with symptoms was 5.4+/-0.6 days). The decrease in salivary IgA secretion rate (pre- to postrace) was 53% greater in the 25 runners reporting URTI (-355+/-45 microg/min) compared to the 81 runners not reporting URTI (-232+/-37 microg/min), (P=0.04). CONCLUSIONS: In summary, nearly 1 in 4 runners reported an URTI episode during the 2-week period following a 160-km race, and the decrease in salivary IgA secretion rate was significantly greater in these runners compared to those not reporting URTI.

Prenatal diagnosis of Bardet-Biedl syndrome by targeted second-trimester sonography.

Bardet-Biedl syndrome (BBS) is an autosomal recessive disorder characterized by mental retardation, obesity, retinal degeneration, polydactyly and syndactyly, diabetes mellitus, hypogenitalism, renal dysplasia and short stature. Definitive molecular diagnosis for BBS is not currently available and counseling of affected families is based on the 25% recurrence risk consistent with autosomal recessive inheritance. Our case presents the first successful use of second trimester targeted sonographic anatomy scanning to prospectively identify a fetus affected with BBS, and indicates that ultrasound can be of critical importance in providing precise as well as timely prenatal diagnosis for families at risk for this serious disorder.

Impact of family structure and stability on academic outcome in preterm children at 10 years of age.

OBJECTIVE: To compare school performance at age 10 years in a cohort of extremely preterm children and term control subjects and to examine the impact of family composition and stability on performance. STUDY DESIGN: Prospective, longitudinal follow-up from birth to 10 years of age of a regional cohort of children born at 24 to 31 weeks of gestational age and sociodemographically matched term control subjects. Family composition, extent of parental care giving, and family moves were tracked sequentially. At 10 years, academic achievement and school performance were ascertained for 118 of 125 (94%) preterm survivors and 119 of 125 (95%) term children. RESULTS: Term children were more likely to demonstrate optimal school outcome (appropriate grade level without additional classroom assistance) than were preterm children (odds ratio 3.4, 95% CI 1.9-6.0). Medical complications related to prematurity had little impact on school outcome. Among preterm children, optimal school outcome was significantly associated with increased parental education, child rearing by 2 parents (regardless of marital status), and stability in family composition and geographic residence over 10 years. These environmental influences were less pronounced among term control subjects. CONCLUSION: Although preterm children performed less well in school than term children, family factors were stronger predictors of school performance than were perinatal complications.

Effect of a peri-parturient eprinomectin treatment of dairy cows on milk production.

AIM: To quantify and economically evaluate the effect on milk production of peri-parturient treatment of dairy cows with eprinomectin. METHODS: On 3 farms in separate geographic areas of New Zealand, 849 first-calf heifers and multiparous cows were ranked and paired within parity, date of calving and expected milk production. Within pairs, cows were randomly allocated to treatment with either a commercial formulation of eprinomectin, applied at a dose rate of 500 mug/kg liveweight, or an equivalent volume of vehicle containing no antiparasitic agent and administered at the same dose volume, generally within the first week post-calving. On each farm, trial cows shared the same pasture. Over a single lactation, records were maintained of milk quantity and content. RESULTS: Trichostrongylid eggs were identified in pre-treatment faecal samples from all farms, verifying the presence of gastrointestinal parasites. Overall 25.5% of the cows sampled were positive for nematode eggs, but only 8% had counts 50 eggs per gram of faeces (epg). Daily milk volume, milk protein and milksolids (yield of milk fat + milk protein) were higher for eprinomectin-treated multiparous cows than for controls (milk volume: 20.36 l/day vs 19.76 l/day, p=0.005; milk protein: 0.700 kg/day vs 0.685 kg/day, p=0.012; milksolids: 1.613 kg/day vs 1.583 kg/day, p=0.031, respectively). The daily value of the increased production from eprinomectin-treated multiparous cows was estimated to be NZ0.034 dollar for milk fat (p=0.095) and NZ0.078 dollar for milk protein (p=0.012), equating to NZ0.104 dollars for milksolids (p=0.031), averaged over the whole lactation. No significant difference in milk production was detected between treated and control first-calf heifers. Averaged over the whole herd, the peri-parturient treatment of multiparous cows and first-calf heifers with eprinomectin increased daily milk volume and milk protein production of treated vs control cows (19.28 l/day vs 18.86 l/day, p=0.020, and 0.661 kg/day vs 0.650 kg/day, p=0.047, respectively). CONCLUSION: These data provide evidence that the use of a peri-parturient treatment of eprinomectin on multiparous cows can increase their production of fluid milk and milksolids.

Chromosomal non-disjunction in human oocytes: is there a mitochondrial connection?

The frequency of chromosome abnormalities due to non-disjunction of maternal chromosomes during meiosis is a function of age, with a sharp increase in the slope of the trisomy-age curve between the ages of 30 and 40 years. The basis of this increase, which is a major cause of birth defects, is unknown at present. In recent years, mutations in mitochondrial (mt) DNA have been associated with a growing number of disorders, including those associated with spontaneous deletions of mtDNA (deltamt DNAs). Intriguingly, these pathogenic deltamtDNAs, which are present at extremely high levels in certain patients, are also present at extremely low levels (detectable only by polymerase chain reaction) in normal individuals. The proportion of such deltamtDNAs in normal muscle is a function of age; the shape of this curve is exponential, with the accelerating part of the curve beginning at approximately 30-40 years. We postulate that, as well as muscle and brain, a similar time-dependent accumulation of deltamtDNAs also occurs in normal oocytes. Since deltamtDNAs are functionally inactive, an accumulation of such aberrant genomes could eventually compromise ATP-dependent energy-utilization in these cells. Furthermore, these deficiencies would also affect the function of the somatic follicular cells that surround, and secrete important paracrine factors to, the oocyte. If there is indeed an age-associated relationship between deltamtDNAs and oocyte age, perhaps errors in meiosis (which is almost certainly an energy, and ATP, dependent process) are related to mutations in mtDNA (primarily deletions, but perhaps point mutations as well) in oocytes and/or the surrounding somatic cells, which result in deficiencies in both mitochondrial function in general and oxidative energy metabolism in particular. This hypothesis would explain many of the non-Mendelian features associated with maternal age-related trisomies, e.g. Down's syndrome.

Comparative cost-effectiveness of ivermectin versus topical organophosphate in feedlot yearlings.

A replicated-pen field trial was performed under commercial feedlot conditions in western Canada to determine the cost-effectiveness of administering ivermectin to yearling beef cattle upon entry to the feedlot after the grazing season, and to establish the level of trichostrongylid gastrointestinal parasite infection in this population, as estimated by fecal egg counts. Six thousand eight hundred and eighty-three, mixed breed, yearling steers were randomly allocated upon arrival at the feedlot to one of 2 experimental groups as follows: Ivermectin, which received topical ivermectin (0.5%) at the rate of 1.0 mL/10 kg body weight; or Fenthion, which received topical fenthion (20%) at the rate of 12 mL/295 kg body weight. There were 15 pens in each experimental group. Final weight, weight gain, average daily gain, and dry matter intake to gain ratio were significantly (P < 0.05) improved in the Ivermectin group as compared with the Fenthion group. There were no significant (P > or = 0.05) differences in initial weight, days on feed, or daily dry matter intake between the experimental groups. The geometric mean fecal egg counts at the time of allocation were 14.7 eggs/5 g and 16.6 eggs/5 g for the Ivermectin and Fenthion groups, respectively (P > or = 0.05). There were no significant (P > or = 0.05) differences in morbidity or mortality between the experimental groups. In the economic analysis, the significant improvements in feedlot performance in the Ivermectin group resulted in a net economic advantage of $4.20 CDN per animal.

Craniofacial and neck anomalies.

The evaluation of the craniofacial region is a multistep process. First, sonographic skill and expertise are required to ascertain these often subtle abnormalities. Next, precise measurements must be obtained in appropriate and reproducible planes. Finally, a thorough search for other related fetal anomalies is essential. Exciting breakthroughs in our understanding of underlying courses and mechanisms can now guide the practitioner not only in deciding whether or not to pursue invasive testing, but which tests to order, particularly if molecular diagnosis may be required. Complementary advances in ultrasound technology, prenatal diagnosis, and genetic research will have the potential to enhance the accuracy of our counseling, management, and overall care of our patients.

Anthelmintic treatment of dairy cows and its effect on milk production.

The results of more than 80 experiments on gastrointestinal parasitism and the impact of anthelmintic treatment on milk production in dairy cattle were reviewed. Abattoir surveys of culled dairy cows, faecal egg counts in milking cows, and serological tests and worm counts in cull cows in milk production studies were collated to assess the level of parasitism in dairy herds. The studies were divided into four general categories: induced infections in previously uninfected cattle; naturally infected cattle treated in mid-lactation; naturally infected cattle treated one to three times during the dry period and/or just before or just after parturition; and naturally infected cattle treated repeatedly from early lactation or given strategic treatments throughout the year. In most studies, the milk production of anthelmintic-treated cattle was compared with that of untreated controls. The anthelmintics investigated included members of the organophosphate, benzimidazole, imidazothiazole and macrocyclic lactone groups. The number of experiments in which the medicated (or uninfected) group had a higher milk yield was compared with the number of experiments in which the control (or infected) group had a higher yield. Overall, the studies demonstrated that grazing dairy cattle are likely to be infected with gastrointestinal nematode parasites, usually Ostertagia ostertagi and Cooperia species. These infections may be present as inhibited larvae, and a periparturient or spring rise is associated with their emergence. There is, at present, no reliable means of determining whether a cow or a herd may be parasitised subclinically at a level sufficient to interfere with milk production. In 70 of 87 experiments (80 per cent) there was an increase in milk production (P < 0.001) after anthelmintic treatment, with a median increase of 0.63 kg/day. In each of the four trial categories, a majority of the studies showed that anthelmintic treatment increased milk production. The yield of milk fat by the medicated cows was greater than by the controls in 26 of the 35 experiments in which that variable was studied (P < 0.01).

Second-trimester molecular prenatal diagnosis of sporadic Apert syndrome following suspicious ultrasound findings.

Apert syndrome, an autosomal dominant disorder characterized by craniosynostosis, mid-facial malformations, symmetric bony syndactyly of hands and feet, and varying degrees of mental retardation, is most frequently caused by a de novo mutation. Two missense mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been found to account for the disorder in approximately 98% of affected patients. Seven cases of prenatal ultrasound diagnosis have been reported. Although one earlier diagnosis has been made in a familial case, sporadic cases have not been definitively diagnosed until the third trimester when craniosynostosis is usually detected. We report a second-trimester molecular diagnosis of a sporadic case, based on the ultrasound observation of fetal 'mitten hands' and craniosynostosis. We discuss the approach to such ultrasound features, given the current availability of molecular diagnosis for Apert syndrome.

The second-trimester fetus with isolated choroid plexus cysts: a meta-analysis of risk of trisomies 18 and 21.

OBJECTIVE: To assess the risk of trisomy 18 and trisomy 21 associated with isolated choroid plexus cysts diagnosed by ultrasound in the second trimester. METHODS OF STUDY SELECTION: We reviewed the unabridged PREMEDLINE and MEDLINE databases for articles written in the English language regarding second-trimester fetal isolated choroid plexus cysts and trisomies 18 and 21, published in the period 1987-1997. Selection criteria included only second-trimester, prospective studies in which the rate of fetal isolated choroid plexus cysts could be calculated, the number of fetuses with trisomy 18 and 21 was reported clearly, and pregnant women of all ages were included, rather than only those at high risk for aneuploidy due to advanced maternal age. TABULATION AND RESULTS: Thirteen prospective studies, comprising 246,545 second-trimester scans, were selected. Among 1346 fetuses with isolated choroid plexus cysts, seven had trisomy 18, and five had trisomy 21. For each study, a 2 x 2 table was constructed and the likelihood ratio of a positive test was computed. The likelihood ratios for trisomies 18 and 21 were found to be homogeneous (P = .08 for trisomy 18, and P = .16 for trisomy 21). The summary likelihood ratio and 95% confidence interval (CI) for each chromosomal abnormality were calculated using the Mantel-Haenszel fixed effects model of meta-analysis. The summary likelihood ratio for trisomy 18 was 13.8 (CI 7.72, 25.14, P < .001) and for trisomy 21 was 1.87 (CI 0.78, 4.46, P = .16). CONCLUSION: The likelihood of trisomy 18 was 13.8 times greater than the a priori risk in fetuses with isolated choroid plexus cysts diagnosed in the second trimester. However, the likelihood of trisomy 21 was not significantly greater than the a priori risk with isolated choroid plexus cysts. The data supported offering pregnant women karyotyping to rule out trisomy 18 when maternal age at delivery is 36 years or older, or when the risk for trisomy 18 detected by serum multiple-marker screen is more than one in 3000.

Effect of preterm birth on pulmonary function at school age: a prospective controlled study.

OBJECTIVE: To assess long-term pulmonary outcome of a regional cohort of children born at < 32 weeks' gestation compared with a matched term control group. STUDY DESIGN: All 125 surviving children born at 24 to 31 weeks' gestation during a 1-year period and a sociodemographically matched term control group were evaluated at age 7 years. RESULTS: Preterm children with previous bronchopulmonary dysplasia (BPD) were twice as likely to require rehospitalization during the first 2 years of life than were preterm children without BPD (53% vs 26%, P < .01). At 7 years of age the BPD group had more airway obstruction than did both preterm children without BPD and the term control group (significantly reduced mean forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow, 25% to 75% vital capacity, all, P < .001). Lung function among preterm children without previous BPD was similar to that of the term control group. Bronchodilator responsiveness was observed twice as often in preterm children with previous BPD (20 of 43, 47%) compared with preterm children without BPD (13 of 53, 25%) or the term control group (23 of 108, 21%, P < .001). These differences remained significant after adjustment was done for birth weight and gestational age. CONCLUSION: Preterm children without BPD demonstrate pulmonary function at school age similar to that of children in a healthy term control group, whereas preterm children with previous BPD demonstrate abnormal pulmonary function.