Molecular Genetic Diagnosis with Targeted Next Generation Sequencing in a Cohort of Turkish Osteogenesis Imperfecta Patients and Their Genotype-phenotype Correlation.

Introduction: Osteogenesis imperfecta (OI) is a group of phenotypically and genetically heterogeneous connective tissue disorders that share similar skeletal anomalies causing bone fragility and deformation. This study aimed to investigate the molecular genetic etiology and determine the relationship between genotype and phenotype in OI patients with targeted next-generation sequencing (NGS). Method: In patients with OI, a targeted NGS analysis panel (Illumina TruSight One) containing genes involved in collagen/bone synthesis was performed on the Illumina Nextseq550 platform. Results: Fifty-six patients (female/male: 25/31) from 46 different families were enrolled in the study. Consanguinity between parents was noted in 15 (32.6%) families. Clinically according to Sillence classification; 18(33.1%) patients were considered to type I, 1(1.7%) type II, 26(46.4%) type III and 11(19.6%) type IV. Median body weight was -1.1 (-6.8, - 2.5) SDS, and height was -2.3 (-7.6, - 1.2) SDS. Bone deformity was detected in 30 (53.5%) of the patients, while 31 (55.4%) were evaluated as mobile. Thirty-six (60.7%) patients had blue sclera, 13 (23.2%) had scoliosis, 12 (21.4%) had dentinogenesis imperfecta (DI), and 2 (3.6%) had hearing loss. Disease-causing variants in COL1A1 and COL1A2 genes were found in 24 (52.1%) and 6 (13%) families, respectively. In 8 (17.3%) of the remaining 16 (34.7%) families, the NGS panel revealed disease-causing variants in three different genes (FKBP10, SERPINF1, and P3H1). Nine (23.6%) of the variants detected in all investigated genes were not previously reported in the literature and were classified to be pathogenic according to ACMG guidelines pathogenity scores. In ten (21.7%) families, a disease-related variant was not found in a total of 13 OI genes included in the panel. Conclusion: Genetic etiology was found in 38 (82.6%) of 46 families by targeted NGS analysis. In addition, 9 new variants were assessed in known OI genes which is a significant contribution to the literature.

African Ancestry Individuals with Higher Educational Attainment Are Resilient to Alzheimer's Disease Measured by pTau181.

Background: Cognitive and functional abilities in individuals with Alzheimer's disease (AD) pathology (ADP) are highly variable. Factors contributing to this variability are not well understood. Previous research indicates that higher educational attainment (EA) correlates with reduced cognitive impairments among those with ADP. While cognitive and functional impairments are correlated, they are distinguishable in their manifestations. Objective: To investigate whether levels of education are associated with functional impairments among those with ADP. Methods: This research involved 410 African American (AA) individuals (Institutional Review Boards 20070307, 01/27/2023) to ascertain whether EA correlates with functional resilience and if this effect varies between APOE ɛ4 carriers and non-carriers. Utilizing EA as a cognitive reserve proxy, CDR-FUNC as a functional difficulties measure, and blood pTau181 as an ADP proxy, the non-parametric Mann-Whitney U test assessed the relationship between EA and CDR-FUNC in individuals with advanced pTau181 levels. Results: The results showed that EA correlated with functional difficulties in AA individuals with high levels of pTau181, such that individuals with high EA are more likely to have better functional ability compared to those with lower EA (W = 730.5, p = 0.0007). Additionally, we found that the effect of high EA on functional resilience was stronger in ɛ4 non-carriers compared to ɛ4 carriers (W = 555.5, p = 0.022). Conclusion: This study extends the role of cognitive reserve and EA to functional performance showing that cognitive reserve influences the association between ADP burden and functional difficulties. Interestingly, this protective effect seems less pronounced in carriers of the strong genetic risk allele ɛ4.

African ancestry APOE e4 non-carriers with higher educational attainment are resilient to Alzheimer disease pathology-specific blood biomarker pTau181.

Cognitive and functional abilities in individuals with Alzheimer disease (AD) pathology (ADP) show greater than expected variability. While most individuals show substantial impairments in these abilities, a considerable number show little or no impairments. Factors contributing to this variability are not well understood. For instance, multiple studies have shown that higher levels of education are associated with reduced cognitive impairments among those with ADP. However, it remains unclear whether higher levels of education are associated with functional impairments among those with ADP. We studied 410 AA individuals with advanced levels of pTau181 (a biomarker for ADP; individuals as those having log 10 (pTau181) level greater than one standard deviation above the mean) to determine whether EA (categorized as low EA for individuals with ≤ 8 years of education and high EA for those with >8 years) promotes functional resilience and whether this effect varies between APOE ε4 carriers and non-carriers. We used the four non-memory components of the Clinical Dementia Rating (CDR) to create a composite score (CDR-FUNC) to evaluate functional difficulties (scored from 0=no impairment to 12=severe). We employed the non-parametric Mann-Whitney U test to assess the relationship between EA and CDR-FUNC in advanced levels of pTau181 individuals. The results showed that EA promotes resilience to functional problems in AA individuals with advanced levels of pTau181, such that individuals with high EA are more likely to have better functional ability compared to those with lower EA (W=730.5, p=0.0007). Additionally, we found that the effect of high EA on functional resilience was stronger in ε4 non-carriers compared to ε4 carriers (W=555.5, p=0.022). This study extends the role of cognitive reserve and EA to functional performance showing that cognitive reserve influences the association between ADP burden and functional difficulties. Interestingly, this protective effect seems less pronounced in carriers of the strong genetic risk allele ε4. The results highlight the intricate interplay of genetic and non-genetic factors in AD progression, suggesting a need for more personalized strategies to manage functional decline in AD.

Clinical and molecular findings in children and young adults with persistent low alkaline phosphatase concentrations.

BACKGROUND: Hypophosphatasia is a rare inherited metabolic disease resulted by ALPL gene mutations. It is characterized by defective bone and teeth mineralization. The phenotypic spectrum is highly variable ranging from lethal perinatal form to mild forms which are only diagnosed in adulthood or remain undiagnosed despite persistently low concentrations of ALP. The aim of this study is to evaluate the clinical phenotype and frequency of ALPL mutations in a group of patient with hypophosphatasaemia. METHODS: Thirty individuals with alkaline phosphatase values below 40 IU/L in at least two assessments and having no alternative explanation for their low ALP concentrations were included in the study. The clinical features and radiological data of the study group were re-investigated for hypophosphatasia-related findings. ALPL sequence analysis was performed using Sanger sequencing. RESULTS: No patient in the study group had severe symptoms, nor had they initially been diagnosed as having hypophosphatasia. Four different heterozygous ALPL mutations (c.542C>T, c.648 + 1G>A, c.657G>T and c.862 + 1G>C) were found in four patients. One splice site mutation (c.862 + 1G>C) was reported for the first time in this study. CONCLUSION: ALPL sequence analysis may help to diagnosing genetic defects in individuals with persistently low ALP concentrations and provide to take preventive measures before symptoms appear. As in the other populations, HPP displays allelic heterogeneity in our population.

Factor 8 Gene Mutation Spectrum of 270 Patients with Hemophilia A: Identification of 36 Novel Mutations

Objective: Hemophilia A (HA) is the most severe X-linked inherited bleeding disorder caused by hemizygous mutations in the factor 8 (F8) gene. The aim of this study is to determine the mutation spectrum of the F8 gene in a large HA cohort from Turkey, and then to establish a phenotype-genotype correlation. Materials and Methods: All HA cases (270 patients) analyzed molecularly in the Ege University Pediatric Genetics Molecular Laboratory between March 2017 and March 2018 were included in this study. To identify intron 22 inversion (Inv22), intron 1 inversion (Inv1), small deletion/insertions, and point mutations, molecular analyses of F8 were performed using a sequential application of molecular techniques. Results: The mutation detection success rate was 95.2%. Positive Inv22 was found in 106 patients (39.3%), Inv1 was found in 4 patients (1.5%), and 106 different disease-causing sequence variants were identified in 137 patients (50.6%). In 10 patients (3.7%), amplification failures involving one or more exonic regions, considered to be large intragenic deletions, were identified. Of 106 different F8 mutations, 36 were novel. The relationship between F8 genotype and inhibitor development was considered significant. Conclusion: A high mutation detection rate was achieved via the broad molecular techniques applied in this study, including 36 novel mutations. With regard to mutation types, mutation distribution and their impact on clinical severity and inhibitor development were found to be similar to those previously reported in other hemophilia population studies.

Evaluation of CNTNAP2 gene rs2107856 polymorphism in Turkish population with pseudoexfoliation syndrome.

PURPOSE: To investigate rs2107856 single-nucleotide polymorphism (SNP) of CNTNAP2 gene in Turkish population with pseudoexfoliation and to correlate clinical characteristics with the genotypic profile. MATERIALS AND METHODS: Forty-three patients with pseudoexfoliation syndrome (PXS), 46 patients with pseudoexfoliation glaucoma (PXG) and 99 healthy controls were enrolled. Comprehensive ophthalmological examination, central corneal thickness measurement and retinal nerve fiber layer thickness analysis of the peripapillary area were performed. Blood samples of 2 mL with EDTA were obtained and sent for genetic analysis. The role of the detected polymorphism on disease tendency along with the genotype and allele frequencies in each group was evaluated. RESULTS: The mean age of the groups was 70.0 ± 8.0 (range 51-86) in PXS, 71.2 ± 8.8 (range 51-93) in PXG and 64.6 ± 8.3 (range 51-91) in controls. The percentages of homozygote individuals were 11.6, 10.9, 21.2%, and heterozygote individuals were 41.9, 45.7, 42.4% in patients with PXS, PXG and controls, respectively. There was no statistically significant difference between groups in terms of both genotype and allele frequencies of rs2107856 (p = 0.429 and p = 0.178, respectively). Retinal nerve fiber layer thickness did not differ between SNP-positive and SNP-negative individuals in PXG, and there was no significant difference between genotype and age, sex, best corrected visual acuity, intraocular pressure, central corneal thickness, cup/disk ratio and retinal nerve fiber layer thickness in any of the groups (p > 0.05). CONCLUSION: rs2107856 SNP of CNTNAP2 gene has no association with PXS and PXG in the evaluated Turkish population.

Clinical and genetic features of L1 syndrome patients: Definition of two novel mutations.

L1 syndrome is a rare X linked recessive disorder caused bygene mutations in the L1 cell adhesion molecule (L1CAM), and characterized by hydrocephalus, intellectual disability, adducted thumbs and spasticity of the legs. The gene encodes a protein which plays an important role in neuronal development. Two unrelated L1 syndrome cases, with global developmental delay and hydrocephalus, were referred to pediatric genetics subdivision for genetic counseling. Bilateral adducted thumbs and spasticity in the lower extremities were also observed in both patients. Molecular analysis revealed two novel hemizygous mutations in the patients: a deletion mutation (c.749delG; p.Ser250Thrfs*51) and a splicing mutation (c.3166+1G>A). To conclude; in male patients with intellectual disability and hydrocephalus, where adducted thumbs are present, L1 syndrome should be considered.

[The Role of Molecular Karyotyping in the Genetic Etiology of Autism]. / Otizmli Olgularda Moleküler Karyotipleme Yöntemi ile Genetik Etiyolojinin Aydinlatilmasi.

OBJECTIVE: The aim of this study was to investigate the deletions and duplications with a molecular karyotyping technique and to elucidate the etiology of autism. METHOD: A total of 31 patients (20 boys and 11 girls) between 4 to 18 years old with normal chromosomal analysis and no Fragile X mutation were diagnosed in the Ege University Child and Adolescent Psychiatry Clinic with autism (according to DSM-IV-TR criteria) and were enrolled in the study. Symptom severity of the patients was evaluated with a Childhood Autism Rating Scale. Blood samples (EDTA collected) were obtained in order to extract DNA. Whole genome molecular karyotyping analyses were performed with Illumina IScan system by chips, which can scan 330.000 Single Nucleotid Polymorphisms (SNPs) to detect structural anomalies with a 10-kb resolution. RESULTS: All patients had copy number variations (CNV) that sized between 20-kb and 3-Mb. All detected CNVs were analyzed by the help of KaryoStudio software and DGV database. The ones which might be causal and pathogenic were selected. Pathogenic CNVs (7 deletions, 2 duplications) were detected in 9 patients (29%). CONCLUSION: As a result, this is the first study whereby a molecular karyotyping technique was successfully used in autism patients in Turkey. Moreover, an intermediate resolution of 330.000 SNP chips were proven to be efficient for molecular karyotyping analysis.