Identification of C12orf4 as a gene for autosomal recessive intellectual disability.

Intellectual disability (ID) is a major health problem in our society. Genetic causes of ID remain unknown because of its vast heterogeneity. Here we report two Finnish families and one Dutch family with affected individuals presenting with mild to moderate ID, neuropsychiatric symptoms and delayed speech development. By utilizing whole exome sequencing (WES), we identified a founder missense variant c.983T>C (p.Leu328Pro) in seven affected individuals from two Finnish consanguineous families and a deletion c.799_1034-429delinsTTATGA (p.Gln267fs) in one affected individual from a consanguineous Dutch family in the C12orf4 gene on chromosome 12. Both the variants co-segregated in the respective families as an autosomal recessive trait. Screening of the p.Leu328Pro variant showed enrichment in the North Eastern sub-isolate of Finland among anonymous local blood donors with a carrier frequency of 1:53, similar to other disease mutations with a founder effect in that region. To date, only one Arab family with a three affected individuals with a frameshift insertion variant in C12orf4 has been reported. In summary, we expand and establish the clinical and mutational spectrum of C12orf4 variants. Our findings implicate C12orf4 as a causative gene for autosomal recessive ID.

A genome-wide linkage and association study of musical aptitude identifies loci containing genes related to inner ear development and neurocognitive functions.

Humans have developed the perception, production and processing of sounds into the art of music. A genetic contribution to these skills of musical aptitude has long been suggested. We performed a genome-wide scan in 76 pedigrees (767 individuals) characterized for the ability to discriminate pitch (SP), duration (ST) and sound patterns (KMT), which are primary capacities for music perception. Using the Bayesian linkage and association approach implemented in program package KELVIN, especially designed for complex pedigrees, several single nucleotide polymorphisms (SNPs) near genes affecting the functions of the auditory pathway and neurocognitive processes were identified. The strongest association was found at 3q21.3 (rs9854612) with combined SP, ST and KMT test scores (COMB). This region is located a few dozen kilobases upstream of the GATA binding protein 2 (GATA2) gene. GATA2 regulates the development of cochlear hair cells and the inferior colliculus (IC), which are important in tonotopic mapping. The highest probability of linkage was obtained for phenotype SP at 4p14, located next to the region harboring the protocadherin 7 gene, PCDH7. Two SNPs rs13146789 and rs13109270 of PCDH7 showed strong association. PCDH7 has been suggested to play a role in cochlear and amygdaloid complexes. Functional class analysis showed that inner ear and schizophrenia-related genes were enriched inside the linked regions. This study is the first to show the importance of auditory pathway genes in musical aptitude.

A novel mutation W388X underlying properdin deficiency in a Finnish family.

Properdin deficiency is a rare immunological disorder inherited as an X-chromosomal recessive trait. Properdin deficiency poses a significant risk for severe meningococcal infections. About 20 mutations have been reported to underlie properdin deficiency. Here we report a large Finnish family with a novel mutation in the properdin gene (CFP). Based on the total absence of properdin activity in a 14-year-old male patient with an infection resembling meningococcal bacteraemia, the coding region and splice sites of the gene were sequenced. The mutation is located in exon 9 and changes guanine to adenine at nucleotide 1164 (c.1164G>A) that causes tryptophan to change to a premature stop codon (W388X). The mother of the patient was shown to be a carrier of the mutation. In total, the mutation was identified in six females and three young males in the family. The mutation must be inherited from the grandfather who had died of an unknown infectious disease. This is the first mutation of the properdin gene identified in Finland.

The secretion of PAPP-A, ADAM12, and PP13 correlates with the size of the placenta for the first month of pregnancy.

OBJECTIVES: Pregnancy Associated Protein A (PAPP-A), A Disintegrin and Metalloproteinase 12 (ADAM12) and Placental Protein 13 (PP13) are secreted from the placental trophoblastic tissue and are involved in normal implantation and placental development. The aim of the study was to assess the connection between the secretion of these proteins and the growth of the gestational sac and the placenta. STUDY DESIGN: In an observational longitudinal study at Oulu University Hospital, women with naturally conceived pregnancies were followed-up weekly to pregnancy week 11. MAIN OUTCOME MEASURES: PAPP-A, ADAM12 and PP13 serum concentrations and their correlation with the volumes of the gestational sac and the placenta were assessed using three-dimensional ultrasonography. RESULTS: The study group consisted of 41 women. The PAPP-A, ADAM12 and PP13 serum concentrations increased continuously from pregnancy week 4 to week 11 and correlated closely with each other. The serum concentrations of PAPP-A, ADAM12 and PP13 also correlated with the volumes of the gestational sac and the placenta up to pregnancy week 8. CONCLUSIONS: The secretion of PAPP-A, ADAM12 and PP13 is closely related to the size of the placenta in the beginning of pregnancy. After 8 weeks of pregnancy, which is the time for luteoplacental shift, the correlation disappears, possibly reflecting the morphologic transformation in the placenta.

Novel PORCN mutations in focal dermal hypoplasia.

Focal dermal hypoplasia (FDH), Goltz or Goltz-Gorlin syndrome, is an X-linked dominant multisystem disorder characterized primarily by involvement of the skin, skeletal system and eyes. We screened for mutations in the PORCN gene in eight patients of Belgian and Finnish origin with firm clinical suspicion of FDH. First, we performed quantitative PCR (qPCR) analysis to define the copy number at this locus. Next, we sequenced the coding regions and flanking intronic sequences of the PORCN gene. Three de novo mutations were identified in our patients with FDH: a 150-kb deletion removing six genes including PORCN, as defined by qPCR and X-array-CGH, and two heterozygous missense mutations; c.992T>G (p.L331R) in exon 11 and c.1094G>A (p.R365Q) in exon 13 of the gene. Both point mutations changed highly conserved amino acids and were not found in 300 control X chromosomes. The three patients in whom mutations were identified all present with characteristic dermal findings together with limb manifestations, which were not seen in our mutation-negative patients. The clinical characteristics of our patients with PORCN mutations were compared with the previously reported mutation-positive cases. In this report, we summarize the literature on PORCN mutations and associated phenotypes.

Effect of mifepristone on the corpus luteum in early pregnancy.

OBJECTIVE: The antiprogestin mifepristone is widely used for medical termination of pregnancy (TOP). Previous studies have suggested that the mechanism of mifepristone is based on its action in the endometrium and myometrium. The aim of this study was to evaluate the possible effects of mifepristone on corpus luteum activity. METHODS: This was a prospective, longitudinal controlled study to which 20 patients undergoing medical TOP (study group) and 20 patients with normal ongoing pregnancy (control group) were recruited. Medical TOP was induced with 200 mg of mifepristone followed by 0.8 mg of misoprostol 2 days later. Three-dimensional ultrasound examinations and hormone assays (progesterone, human chorionic gonadotropin, and 17-hydroxyprogesterone) were performed in both groups on the day of, and 2 days after, administration of mifepristone. Total volume (vascularized + non-vascularized) of the dominant (containing corpus luteum) and non-dominant ovary and serum hormone levels were measured. RESULTS: After administration of mifepristone, a decrease in serum progesterone levels was observed with a simultaneous decrease in the non-vascularized volume of the dominant ovary in the study group. No such changes were observed in the control group. CONCLUSIONS: The observations indicate that, in addition to trophoblastic tissue, the corpus luteum is also the target of mifepristone.

Complement factor H variant Y402H is not a risk factor for preeclampsia in the Finnish population.

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.

Genome-wide linkage scan for loci of musical aptitude in Finnish families: evidence for a major locus at 4q22.

BACKGROUND: Music perception and performance are comprehensive human cognitive functions and thus provide an excellent model system for studying human behaviour and brain function. However, the molecules involved in mediating music perception and performance are so far uncharacterised. OBJECTIVE: To unravel the biological background of music perception, using molecular and statistical genetic approaches. METHODS: 15 Finnish multigenerational families (with a total of 234 family members) were recruited via a nationwide search. The phenotype of all family members was determined using three tests used in defining musical aptitude: a test for auditory structuring ability (Karma Music test; KMT) commonly used in Finland, and the Seashore pitch and time discrimination subtests (SP and ST respectively) used internationally. We calculated heritabilities and performed a genome-wide variance components-based linkage scan using genotype data for 1113 microsatellite markers. RESULTS: The heritability estimates were 42% for KMT, 57% for SP, 21% for ST and 48% for the combined music test scores. Significant evidence of linkage was obtained on chromosome 4q22 (LOD 3.33) and suggestive evidence of linkage at 8q13-21 (LOD 2.29) with the combined music test scores, using variance component linkage analyses. The major contribution of the 4q22 locus was obtained for the KMT (LOD 2.91). Interestingly, a positive LOD score of 1.69 was shown at 18q, a region previously linked to dyslexia (DYX6) using combined music test scores. CONCLUSION: Our results show that there is a genetic contribution to musical aptitude that is likely to be regulated by several predisposing genes or variants.

The effect of complement factor H Y402H polymorphism on the outcome of photodynamic therapy in age-related macular degeneration.

PURPOSE: Photodynamic therapy (PDT) has been widely used in the treatment of age-related macular degeneration (AMD). The complement cascade has an important role in the tissue reactions occurring after PDT. The Y402H polymorphism of the complement factor H (CFH) gene has been identified as a risk factor for AMD. Since CFH is central in the regulation of the complement system the authors wanted to analyze whether the CFH Y402H polymorphism modifies the PDT outcome in AMD. METHODS: A total of 88 patients having been treated with PDT and without further scheduled PDT sessions were analyzed. Depending on the situation at their final PDT session the patients were classified retrospectively as PDT-responders or PDT-nonresponders. All patients were genotyped for the CFH Y402H polymorphism. RESULTS: The proportion of PDT-responders was 18/26 (69.2%) in patients homozygous for the CFH Y402H risk allele, 34/50 (68.0%) in heterozygous, and 7/12 (58.3%) in patients with the normal genotype (p=0.520). The median number of PDT treatments of the PDT-responders was three for all the genotypes. CONCLUSIONS: The dysfunction of the CFH related to the risk of AMD and caused by the Y402H polymorphism does not modify the outcome of PDT. Genotyping for CFH Y402H cannot be used to select patients for this treatment.

The T/G 13915 variant upstream of the lactase gene (LCT) is the founder allele of lactase persistence in an urban Saudi population.

BACKGROUND: The prevalence of lactase persistence is high in Saudi Arabia. OBJECTIVE: To identify a DNA variant for the lactase persistence/non-persistence trait in adult Arabs in Saudi Arabia. METHODS: We sequenced DNA from 432 anonymous neonatal blood donors from five different regions of Saudi Arabia to cover the 400 bp region surrounding the previously identified lactase persistence/non-persistence variant C/T-13910 residing in intron 13 of the MCM6 gene. RESULTS: Two anonymous blood donors carried the C/T-13910 genotype. One variant, T/G -13915, residing 5 bp upstream of the C/T-13910 variant, was present in 332 of 432 (76.9%) of the neonatal samples, compatible with previous prevalence figures of lactase persistence in urban Saudi populations. Determination of disaccharidase activities in 25 intestinal biopsy samples showed a highly significant correlation between lactase activity and the T/G-13915 genotypes (p<0.001; Fisher exact test) as well as between the L:S ratio and the aforementioned genotypes (p<0.001; Fisher exact test). CONCLUSION: The T/G-13915 variant is the founder mutation of lactase persistence in an urban Saudi population. The results obtained here have implications for genetic testing of adult-type hypolactasia and to analysis of human evolution, the origin of cattle domestication and migrations of the populations in the Arabian peninsula.

Screening of mutations in the PHF8 gene and identification of a novel mutation in a Finnish family with XLMR and cleft lip/cleft palate.

We investigated the prevalence of mutations in the PHD finger protein 8 (PHF8) gene in X-linked mental retardation (XLMR) and facial cleft starting from the original cohort of 7712 patients operated on since 1 January 1950 for cleft lip/cleft palate in the Cleft Centre at the Helsinki University Hospital. From this nationwide material, 18 patients including one family with two male patients with cleft lip/cleft palate and unknown cause of mental retardation (MR) were sequenced for the coding regions and splice sites of the PHF8 gene. A novel missense mutation c.836C>T of the PHF8 gene was identified in a Finnish family with multiple-affected male patients. The mutation resides in exon 8 and changes phenylalanine to serine (F279S) in the functionally important Jmonji C domain of the protein. The clinical phenotype of the male patients was characterized by mild MR, mild dysmorphic features, unilateral cleft lip and cleft palate in one and bilateral cleft lip and cleft palate in the other sibling. The mutation was not present in 200 anonymous blood donors (approximately 300 X-chromosomes). To our knowledge, F279S is the third mutation of the PHF8 gene identified so far.

Juvenile-onset neuronal ceroid lipofuscinosis with infantile CLN1 mutation and palmitoyl-protein thioesterase deficiency.

Accurate diagnosis, especially in progressive hereditary diseases, is essential for the treatment and genetic counseling of the patient and the family. Neuronal ceroid lipofuscinoses (NCL) are amongst the most common groups of neurodegenerative diseases. Infantile, juvenile, and adult-onset types with multiple genotype-phenotype associations have been described. A fluorimetric enzyme assay for palmitoyl protein thioesterase (PPT) from leukocytes and fibroblasts has been previously developed to confirm the diagnosis of infantile NCL. We describe a patient with juvenile-onset NCL phenotype with a new CLN1 mutation and deficient PPT activity. Over 40 different mutations have been found in patients with PPT deficiency, indicating that screening for known mutations is not an efficient way to diagnose this disorder. Therefore, PPT enzyme analysis should precede mutation analysis in suspected PPT deficiency, particularly in patients with granular osmiophilic deposits (GROD) or in patients who have negative ultrastructural data. The use of enzyme assay led to the diagnosis of this patient with juvenile-onset Finnish variant NCL with PPT deficiency, and we expect that greater awareness of the utility of the enzymatic assay may lead to identification of other similar cases awaiting a definitive diagnosis.

A biopsy-based quick test in the diagnosis of duodenal hypolactasia in upper gastrointestinal endoscopy.

BACKGROUND AND STUDY AIMS: The usefulness of a new quick test for endoscopic diagnosis of adult-type hypolactasia was tested in duodenal biopsies. In this test, an endoscopic biopsy from the postbulbar duodenum is incubated with lactose on a test plate, and a color reaction develops within 20 min as a result of hydrolyzed lactose (a positive result) in patients with normolactasia, whereas no reaction (a negative result) develops in patients with severe hypolactasia. PATIENTS AND METHODS: Two postbulbar duodenal biopsies were taken from 80 prospectively enrolled adult outpatients with dyspepsia. The biopsies were used for the Quick Lactase Test (Biohit PLC, Helsinki, Finland) and in biochemical disaccharidase (lactase, sucrase, and maltase) assays. In addition, the C/T (-13,910) genotype was determined from DNA extracted from gastric antral biopsies using polymerase chain reaction sequencing in genomic analysis of adult-type hypolactasia. RESULTS: Twenty-one of 22 patients (95 %; 95 % CI, 87 - 100 %) with biochemical lactase activity < 10 U/g protein, but none of the 58 patients with lactase activity of 10 U/g protein or more had a negative result in the Quick Lactase Test. Seven of the 80 patients (9 %; 95 % CI, 3 - 15 %) had a Quick Lactase Test result that indicated mild hypolactasia (a mild color reaction). All patients with celiac disease (n = 6) had a negative Quick Lactase Test result. Nine of 74 patients (six patients with celiac disease were excluded) had a CC (-13,910) genotype in genomic testing, indicating adult-type hypolactasia. All of them had negative test results with the Quick Lactase Test. Twenty-six patients had a TT genotype, indicating normolactasia, and none of these patients had a negative test result in the Quick Lactase Test. Six of 39 patients (15 %; 95 % CI, 4 - 27 %) with a CT genotype had a negative result in the Quick Lactase Test. CONCLUSIONS: The Quick Lactase Test effectively identifies patients with severe duodenal hypolactasia. In comparison with CC (adult-type hypolactasia) and TT individuals (normolactasia), the sensitivity and specificity of the Quick Lactase Test result was 100 %. In comparison with biochemical lactase assays, the sensitivity and specificity of a negative Quick Lactase Test for indicating hypolactasia (lactase activity < 10 U/g protein) were 95 % (95 % CI, 87 - 100 %) and 100 %, respectively.

Evaluation of factor V Leiden, prothrombin and methylenetetrahydrofolate reductase gene mutations in patients with severe pregnancy complications in northern Finland.

BACKGROUND: Thrombosis in placenta may lead to severe pregnancy complications. Most important inherited thrombophilias are factor V Leiden mutation, prothrombin mutation, and methylenetetrahydrofolate reductase mutation. The aim of our research was to evaluate the prevalence of inherited thrombophilias in severe pregnancy complications and in normal pregnancies. MATERIAL AND METHODS: The study subjects with severe preeclampsia, intrauterine growth restriction, placental abruption or fetal death were collected during the period 1999-2004 from Oulu University Hospital. We also collected during the same period voluntary parturients with normal pregnancy outcome as the control group. FVL, FII, and MTHFR gene mutations of the patients and controls were analyzed. RESULTS: We found a significant difference in the prevalence of FVL mutation between the groups. There were 9.5% FVL mutations in the study group compared to 1.8% in the control group; the observed difference between prevalences was 7.7% (95% CI 2.0-13.4). No statistical difference was found in the FII or MTHFR mutations between the groups. All FV and FII mutations were heterozygous and all the MTHFR mutations homozygous. CONCLUSION: Women with thrombophilia have a risk for severe pregnancy complications. Randomized controlled trials are needed to assess the influence of low-molecular-weight heparin in pregnant women with thrombophilia.

Independent replication and initial fine mapping of 3p21-24 in Asperger syndrome.

BACKGROUND: Asperger syndrome is characterised by abnormalities in social interaction as well as repetitive and stereotyped behaviours and interests. The trait is thought to display complex inheritance, but in a subset of families the inheritance resembles the autosomal dominant model. Linkage to 3p14-24 has recently been reported in Asperger syndrome in Finnish families with a maximum multipoint NPL(all) of 3.32 at D3S2432. METHODS: We have replicated linkage findings to 3p21-24 in 12 new extended Asperger syndrome families. Linkage analyses were performed separately for the 12 new families, and linkage and association analyses were also performed jointly with data from the original genome-wide screen. RESULTS: Best two point and multipoint logarithm of the odds (LOD) scores in analyses of both data sets were obtained at D3S2432 (NPL(all) = 3.83) with both subsets of families contributing to linkage. Association analysis of the combined data set produced a trend towards association with D3S2432 and D3S1619. CONCLUSIONS: This study further validates 3q21-24 as a candidate region for Asperger syndrome.

A heterogeneity-based genome search meta-analysis for autism-spectrum disorders.

Autism and autism-spectrum disorders exhibit high heritability, although specific susceptibility genes still remain largely elusive. We performed a heterogeneity-based genome search meta-analysis (HEGESMA) of nine genome scans on autism or autism-spectrum disorders. Each genome scan was separated in 30 cM bins and the maximum linkage statistic from each bin was ranked. Significance for each bin's average rank and for between-scan heterogeneity (dis-similarity in the average ranks) was obtained through Monte Carlo tests. For autism, data from 771 affected sibpairs were synthesized across six separate genome scans. Region 7q22-q32 reached genome-wide significance both in weighted and unweighted analyses, with evidence for significantly low between-scan heterogeneity. The flanking chromosomal region 7q32-qter reached the less stringent threshold of suggestive significance, with no evidence for low between-scan heterogeneity. For autism-spectrum disorders (634 affected sibpairs from five separate scans), no chromosomal region reached genome-wide significance. However, suggestive significance was reached for the chromosomal regions 17p11.2-q12 and 10p12-q11.1 in weighted analyses. There was evidence for significantly high between-scan heterogeneity for the former region. The meta-analysis suggests that the 7q22-q32 region should be further scrutinized for autism susceptibility genes, while autism-spectrum disorders seem to have quite diverse linkage signals across scans, possibly suggesting genetic heterogeneity across subsyndromes and subpopulations.

Evaluation of endometrial receptivity during in-vitro fertilization using three-dimensional power Doppler ultrasound.

OBJECTIVE: To compare sonographic endometrial characteristics in in-vitro fertilization (IVF) cycles between women who conceive and those who do not. METHODS: Thirty-five women undergoing IVF treatment participated in the study. Using three-dimensional (3D) power Doppler ultrasound, we assessed endometrial patterns, volume and vascularization, after follicle stimulating hormone (FSH) stimulation but before human chorionic gonadotropin (hCG) administration (referred to hereafter as 'after FSH stimulation') and again on the day of oocyte retrieval. RESULTS: The pregnancy rate was 37% (13/35). After FSH stimulation, 29 of the 35 women had a triple-line endometrial pattern, compared with five out of 35 on the day of oocyte retrieval. In those who had a triple-line pattern after FSH stimulation the pregnancy rate was 44.8% (13/29) and it was 0% (0/6) in those with a homogeneous pattern (chi-square test, P = 0.039). If a triple-line pattern was present on the day of oocyte retrieval the pregnancy rate was 80.0% (4/5), whereas if the pattern was homogeneous the pregnancy rate was 30.0% (9/30) (P = 0.032). There were no differences between those who conceived and those who did not in endometrial thickness, volume or vascularization on either day examined. Endometrial volume decreased significantly after hCG injection in women who conceived, but not in those who did not conceive. In both groups endometrial and subendometrial vascularization decreased after hCG injection, while the endometrial thickness remained unchanged. CONCLUSIONS: The existence of a homogeneous endometrial pattern after FSH stimulation seems to be a prognostic sign of an adverse outcome in IVF, while a triple-line pattern after FSH stimulation and a decrease in endometrial volume appear to be associated with conception.