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Background and aims: The mechanism of the developmental downregulation of the lactase-phlorizin hydrolase (LPH) gene underlying adult-type hypolactasia is unknown. We have determined the functional significance of the recently identified [...]

Objective: To study the relationships of molecularly defined lactose malabsorption (LM) and self-reported lactose intolerance (LI) to bone mineral density (BMD) and fractures among Finnish postmenopausal women. Design: A cross-sectional study of two cohorts. Setting: Helsinki University Central Hospital. Subjects: One cohort was population-based and comprised 453 women, aged 62-78 (mean 69) y. Another comprised 52 women, aged 69-85 (mean 75) y, with osteoporotic fractures and 59 control women, aged 69-83 (mean 74) y, without osteoporosis. Methods: A single nucleotide polymorphism of the lactase (LCT) gene at chromosome 2q21-22 was studied. It shows complete association with intestinal disaccharidase activity, with the genotype CC[sub.-13 910] meaning adult-type hypolactasia (primary LM) and the genotypes CT[sub.-13 910] and TT[sub.-13 910] lactose absorption. BMD of the heel was measured by dual-energy X-ray absorptiometry (DXA). Results: In the population-based cohort, 16.0% of women had self-reported LI but only 15.3% of them had the CC[sub.-13 910] genotype. Calcium intake from dairy products (P=0.10) and BMD, adjusted for age, weight, height, exercise, smoking, and estrogen use (P=0.71) were similar for the genotypes. Women with self-reported LI had reduced calcium intake from dairy products (P [less than] 0.0001) but they were more frequent users of calcium supplements than lactose-tolerants (P [less than] 0.0001). Adjusted BMD was similar for lactose intolerant and tolerant women (P=0.60). Of 104 women with previous fracture in the population-based cohort, 13.5% had the CC[sub.-13 910] genotype, which did not differ from the prevalence of 19.3% among 347 women without fractures (P=0.29). The frequency of the CC[sub.-13 910] genotype (23.1%) for 52 women with established osteoporosis was similar as for 59 control women (15.3%) (P=0.19). Conclusion: Molecularly defined LM and self-reported LI are not risk factors for osteoporosis, if calcium intake from diet and/or supplements remains sufficient. Our study confirms the poor correlation between self-reported LI and LM established by different techniques. Sponsorhip: Supported by the Research Funding from Helsinki University Central Hospital (Erityisvaltionosuus) and by the Miina Sillanp#228;#228; Foundation, Helsinki, Finland. European Journal of Clinical Nutrition (2005) 59, 1105-1111. doi: 10.1038/sj.ejcn.1602219; published online 6 July 2005 Keywords: lactase, lactose intolerance, lactose malabsorption, genotype, bone mineral density, fractures, osteoporosis, Author(s): N Enattah [1]; T Pekkarinen [2]; M J Valimaki [3]; E Loyttyniemi [4]; I Jarvela [1, 5] Introduction Osteoporosis is a multi-factorial disease caused by both genetic and environmental [...]

Objective:: Lactase persistence (LP), the ability to maintain a high lactase activity throughout life, has been suggested to be a possible risk factor for diabetes. Recently, a single nucleotide polymorphism C (-13910) T, residing 14 kb from the 5' end of the lactase (LCT) gene was shown to be associated with LP. Here we have studied the relationship between C (13910) T polymorphism and diabetes in the Finnish population. Patients and design:: In all, 1455 patients with type I and 615 with type II diabetes and 446 nondiabetic controls in the Finnish population were genotyped for the C (-13910) T polymorphism by PCR minisequencing. Results:: No differences were detected in the LP genotype frequencies (CTTT) between diabetic and nondiabetic subjects. Conclusions:: We conclude that the C (-13910) T polymorphism associated with lifelong LP is not a risk factor for type I or type II diabetes in the Finnish population. European Journal of Clinical Nutrition (2004) 58, 1319-1322. doi: 10.1038/sj.ejcn.1601971 Published online 31 March 2004 Keywords: lactase persistence, lactose malabsorption, single nucleotide polymorphism, diabetes, Author(s): N S Enattah [1, 2]; C Forsblom [3, 4]; H Rasinpera [1]; T Tuomi [3, 5]; P-H Groop [3, 4]; I Jarvela [1, 6]; the FinnDiane Study Group The [...]

Objective: Variations in complement factor H, which down-regulates the activity of the alternative complement pathway, have been associated with different vascular disorders. Here we examine whether factor H variation is involved in the etiology of preeclampsia.Methods: We studied 110 women with preeclampsia and 99 controls for complement factor H variations by sequencing.Results: No significant differences in the genotype or allele frequencies of the Y402H variant were detected between the two groups. No sequence variations were detected in the short consensus repeat domain 20 of the gene.Conclusions: Neither the Y402H variant, nor mutations in the short consensus repeat domain 20 of the gene is associated with preeclampsia. For examination of possible links to other polymorphisms or detection of small genotypic effects, studies in larger sample sets are warranted. [ABSTRACT FROM AUTHOR]

Background: Variants in HECW2 have recently been reported to cause a neurodevelopmental disorder with hypotonia, seizures and impaired language; however, only six variants have been reported and the clinical characteristics have only broadly been defined., Methods: Molecular and clinical data were collected from clinical and research cohorts. Massive parallel sequencing was performed and identified individuals with a HECW2- related neurodevelopmental disorder., Results: We identified 13 novel missense variants in HECW2 in 22 unpublished cases, of which 18 were confirmed to have a de novo variant. In addition, we reviewed the genotypes and phenotypes of previously reported and new cases with HECW2 variants (n=35 cases). All variants identified are missense, and the majority of likely pathogenic and pathogenic variants are located in or near the C-terminal HECT domain (88.2%). We identified several clustered variants and four recurrent variants (p.(Arg1191Gln);p.(Asn1199Lys);p.(Phe1327Ser);p.(Arg1330Trp)). Two variants, (p.(Arg1191Gln);p.(Arg1330Trp)), accounted for 22.9% and 20% of cases, respectively. Clinical characterisation suggests complete penetrance for hypotonia with or without spasticity (100%), developmental delay/intellectual disability (100%) and developmental language disorder (100%). Other common features are behavioural problems (88.9%), vision problems (83.9%), motor coordination/movement (75%) and gastrointestinal issues (70%). Seizures were present in 61.3% of individuals. Genotype-phenotype analysis shows that HECT domain variants are more frequently associated with cortical visual impairment and gastrointestinal issues. Seizures were only observed in individuals with variants in or near the HECT domain., Conclusion: We provide a comprehensive review and expansion of the genotypic and phenotypic spectrum of HECW2 disorders, aiding future molecular and clinical diagnosis and management., Competing Interests: Competing interests: LF, KW, IMW, FZ, EAN and ET are employees of GeneDx. All other coauthors have no conflicts of interest related to the work in this manuscript., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The genetic architecture of hearing impairment in Finland is largely unknown. Here, we investigated two Finnish families with autosomal recessive nonsyndromic symmetrical moderate-to-severe hearing impairment., Methods: Exome and custom capture next-generation sequencing were used to detect the underlying cause of hearing impairment., Results: In both Finnish families, we identified a homozygous pathogenic splice site variant c.637+1G>T in CAPB2 that is known to cause autosomal recessive nonsyndromic hearing impairment. Four CABP2 variants have been reported to underlie autosomal recessive nonsyndromic hearing impairment in eight families from Iran, Turkey, Pakistan, Italy, and Denmark. Of these variants, the pathogenic splice site variant c.637+1G>T is the most prevalent. The c.637+1G>T variant is enriched in the Finnish population, which has undergone multiple bottlenecks that can lead to the higher frequency of certain variants including those involved in disease., Conclusion: We report two Finnish families with hearing impairment due to the CABP2 splice site variant c.637+1G>T., (© 2022 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Clinical presentations of mutations in the IQSEC2 gene on the X-chromosome initially implicated to cause non-syndromic intellectual disability (ID) in males have expanded to include early onset seizures in males as well as in females. The molecular pathogenesis is not well understood, nor the mechanisms driving disease expression in heterozygous females. Using a CRISPR/Cas9-edited Iqsec2 KO mouse model, we confirm the loss of Iqsec2 mRNA expression and lack of Iqsec2 protein within the brain of both founder and progeny mice. Both male (52%) and female (46%) Iqsec2 KO mice present with frequent and recurrent seizures. Focusing on Iqsec2 KO heterozygous female mice, we demonstrate increased hyperactivity, altered anxiety and fear responses, decreased social interactions, delayed learning capacity and decreased memory retention/novel recognition, recapitulating psychiatric issues, autistic-like features, and cognitive deficits present in female patients with loss-of-function IQSEC2 variants. Despite Iqsec2 normally acting to activate Arf6 substrate, we demonstrate that mice modelling the loss of Iqsec2 function present with increased levels of activated Arf6. We contend that loss of Iqsec2 function leads to altered regulation of activated Arf6-mediated responses to synaptic signalling and immature synaptic networks. We highlight the importance of IQSEC2 function for females by reporting a novel nonsense variant c.566C > A, p.(S189*) in an elderly female patient with profound intellectual disability, generalised seizures, and behavioural disturbances. Our human and mouse data reaffirm IQSEC2 as another disease gene with an unexpected X-chromosome heterozygous female phenotype. Our Iqsec2 mouse model recapitulates the phenotypes observed in human patients despite the differences in the IQSEC2/Iqsec2 gene X-chromosome inactivation between the species., (© 2019 Jackson et al.)

Objective: To investigate first trimester levels of ADAM12 in trisomy 18 and 13 pregnancies and whether incorporating ADAM12 in the LifeCycle™ risk calculation program of trisomy 18 and trisomy 13 screenings can improve the detection rates of trisomies 18 and 13., Methods: ADAM12 was incorporated in the LifeCycle™ risk calculation program. A specific algorithm with cut-off of 1:200 for screening of trisomies 18 and 13 was employed. Detection rates for trisomies 18 and 13 were calculated., Results: There was a significant difference in ADAM12 levels between trisomy 18 pregnancies and controls during the gestation weeks 9 + 0 - 10 + 6, but not thereafter. In trisomy 13 pregnancies there was no difference in weeks 9 + 0 - 10 + 6, but there was in 11 + 0 - 12 + 6. The specific algorithms for trisomies 18 and 13 combined with algorithm for trisomy 21 yielded detection rates of 73.7% and 66.7%, respectively. The combined false positive rate was 4.6%. Adding ADAM12, the detection rate for trisomy 18 was the same, at 73.7% and for trisomy 13, at 66.7%., Conclusion: ADAM12 did not improve the detection rate.

We analyzed the frequency and possible causes of false-negative (Fn) screening results in first-trimester combined Down syndrome screening in Finland. During the study period (May 1, 2002, to December 31, 2008), 76,949 voluntary women with singleton pregnancies participated in screening. Maternal age at screening, week of gestation, levels of pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (fβ-hCG), and nuchal translucency (NT) measurement were compared and statistically analyzed between true-positive (Tp) and Fn cases. There were a total of 188 Down syndrome cases (1:409) in the screened population; 154 confirmed Tp and 34 Fn cases. Most Fn cases (n = 25) occurred at 12 + 0 to 13 + 6 weeks' gestation and only nine Fn cases presented between 10 and 11 weeks' gestation. According to the logistic regression analysis, the NT measurement was the most powerful discriminating factor in Fn screening results and accounted for 37.2% of Fn results. The second most important factor was fβ-hCG, adding 14.0% to R(2), followed by PAPP-A, which contributed a further 14.3%. The chosen parameters explain 83.9% of Fn results, but 16.1% remain due to unknown factor(s). All investigated parameters contributed to Fn screening results, but fetal NT was the most discriminating factor leading to an Fn screening result., (Copyright © 2012 by Thieme Medical Publishers, Inc.)

The maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) were reduced in hormonally stimulated pregnancies in the in vitro fertilization and intracytoplasmic sperm injection groups (N=176; PAPP-A: 0.82) and in the entire assisted reproduction group (N=282; PAPP-A: 0.83) as compared with controls (N=24,783; PAPP-A: 0.94). However, the false-positive rate of first-trimester combined screenings was not statistically significantly increased in assisted reproduction pregnancies after adjustment for maternal age., (Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Lactase non-persistence is a condition where lactase activity is decreased in the intestinal wall after weaning. In European derived populations a single nucleotide polymorphism (SNP) C/T-13910 residing 13.9 kb upstream from the lactase gene has been shown to define lactase activity, and several other single nucleotide polymorphisms (G/C-14010 T/G-13915, C/G-13907 and T/C-13913) in the same region have been identified in African and Middle East populations., Results: The T-13910 allele most common in European populations was present in 21.8% mixed ancestry (N = 62) individuals and it was absent in the Xhosa (N = 109) and Ghana (N = 196) subjects. Five other substitutions were also found in the region covering the previously reported variants in African and Middle East populations. These included the G/C-14010 variant common in Kenyan and Tanzanian populations, which was present in 12.8% of Xhosa population and in 8.1% of mixed ancestry subjects. Two novel substitutions (C/T-14091 and A/C-14176) and one previously reported substitution G/A-13937 (rs4988234) were less common and present only in the Xhosa population. One novel substitution G/A-14107 was present in the Xhosa and Ghanaian populations. None of the other previously reported variants were identified., Conclusion: Identification of the G/C-14010 variant in the Xhosa population, further confirms their genetic relatedness to other nomadic populations members that belong to the Bantu linguistic group in Tanzania and Kenya. Further studies are needed to confirm the possible relationship of the novel substitutions to the lactase persistence trait.

Objective: To investigate whether incorporating the measurement of ADAM12 in the risk calculation program LifeCycle, can improve Down screening in the first trimester., Methods: In a retrospective case control study, maternal serum ADAM12 concentrations were measured and compared in Down syndrome cases (n = 53) and in controls (n = 226) obtained from first trimester (9-12 weeks) screening samples in Oulu and Kuopio University Hospitals. Median concentration ( microg/l), observed and regressed (weight corrected) MoMs of ADAM12 were calculated., Results: There was a significant difference in ADAM12 levels between Downs and controls during the pregnancy weeks 9 + 0 to 10 + 6, but not thereafter. By adding ADAM12 to the marker set used in the risk calculation program, one screening false negative Down syndrome case occurred in the affected population, which did not alter false positive rate., Conclusion: Adding ADAM12 as a parameter in Down screening did not cause radical changes in the risk value. The test might be useful at 9 and 10 weeks in which it might have the potential to improve the performance of the risk assessment especially for women receiving a result close to the high-risk cut-off. The real influence of ADAM12 remains to be elucidated in larger studies incorporating ADAM12 to the risk calculation program.