Survey of patient satisfaction with genetic counseling services in Korea.

Since the 1990s, genetic clinics have been established in South Korea, enabling the provision of clinical genetics services. However, genetic counseling services are not widely used in the medical system. In contrast, recently, the demand for genetic counseling has increased due to the rapid development of genomic medicine. Therefore, it is important for medical geneticists and genetic counselors to collaboratively provide genetic counseling services. This study aimed to evaluate the perception and satisfaction of patients with rare genetic diseases and their families regarding genetic counseling services provided by a genetics team at the medical genetics center of a tertiary general hospital for rare genetic diseases. From April to November 2021, a survey was conducted with 203 individuals, including 111 and 92 individuals in the patient and family groups, respectively. Overall, 164 individuals (80.8%) responded that they were aware of genetic counseling services, and 135 individuals (66.5%) responded that they were aware of the role of genetic counselors. Patients and their families wanted to receive information about the following from genetic counseling: clinical manifestation and prognosis of the diagnosed disease (78.8%), treatment and management of the disease (60.6%), risk of recurrence within the family (55.7%), treatment options and alternatives for family and prenatal testing, and various support services. The score of satisfaction with genetic counseling services provided by the genetics team was 8.19 ± 1.68 out of 10. Patients with rare genetic diseases and their families were satisfied with genetic counseling services regarding their diseases, test results, and treatment options. Moreover, the patients could receive psychosocial support and referrals to other medical service providers and support services. As a genetic team approach, collaboration between medical geneticists and certified genetic counselors would be useful in providing information and in diagnosing, treating, and managing patients.

Identification of a rare homozygous c.790C>T variation in the TFB2M gene in Korean patients with autism spectrum disorder.

Mitochondrial dysfunction and subsequent enhanced oxidative stress is implicated in the pathogenesis of autism spectrum disorder (ASD). Mitochondrial transcription factor B2 (TFB2M) is an essential protein in mitochondrial gene expression. No reports have described TFB2M mutations and variations involved in any human diseases. We identified a rare homozygous c.790C>T (His264Tyr) variation in TFB2M gene in two Korean siblings with ASD by whole-exome sequencing. The roles of the TFB2M variation in the pathogenesis of ASD were investigated. Patient fibroblasts revealed increased transcription of mitochondrial genes and mitochondrial function in terms of ATP, membrane potential, oxygen consumption, and reactive oxygen species (ROS). Overexpression of the TFB2M variant in primary-cultured fibroblasts demonstrated significantly increased transcription of mitochondrial genes and mitochondrial function compared with overexpression of wild-type TFB2M. Molecular dynamics simulation of the TFB2M variant protein suggested an increase in the rigidity of the hinge region, which may cause alterations in loading and/or unloading of TFB2M on target DNA. Our results suggest that augmentation of mitochondrial gene expression and subsequent enhancement of mitochondrial function may be associated with the pathogenesis of ASD in Korean patients.

Identification of the rare compound heterozygous variants in the NEB gene in a Korean family with intellectual disability, epilepsy and early-childhood-onset generalized muscle weakness.

We examined a Korean family with complex phenotypes characterized by intellectual disability, epilepsy and early-childhood-onset generalized muscle weakness. Since we did not find any abnormality using several conventional genetic tests for detection of chromosomal aberrations, gene copy number variations and mitochondrial gene mutations, we aimed to identify disease-causing genetic alteration(s) in this family. We conducted whole-exome sequencing (WES) in this family. After filtering the WES data, we compared five exome sequences of two affected siblings, one unaffected sibling and the unaffected parents, and we determined the allele frequency of the identified variants in an Asian population. Finally, we selected one candidate variant pair which is unique in the patients and corresponds to an autosomal recessive genetic model. The two affected siblings had the same compound heterozygous variation in the NEB gene encoding nebulin, which was composed of two different missense variants: c.2603T>C (p.L868P) in exon 27 and c.21340C>T (p.R7114W) in exon 143. We confirmed these variations by Sanger sequencing. On the basis of the fundamental role of nebulin in the brain and skeletal muscles, we concluded that this compound heterozygous NEB variation may be a sound candidate for the disease-causing mutation in this family. Since the patients are characterized by generalized muscle weakness together with neurodevelopmental phenotypes, it is suggested that NEB mutations could manifest more diverse phenotypes than those previously described.

Association of the I264T variant in the sulfide quinone reductase-like (SQRDL) gene with osteoporosis in Korean postmenopausal women.

To identify novel susceptibility variants for osteoporosis in Korean postmenopausal women, we performed a genome-wide association analysis of 1180 nonsynonymous single nucleotide polymorphisms (nsSNPs) in 405 individuals with osteoporosis and 722 normal controls of the Korean Association Resource cohort. A logistic regression analysis revealed 72 nsSNPs that showed a significant association with osteoporosis (p<0.05). The top 10 nsSNPs showing the lowest p-values (p = 5.2×10-4-8.5×10-3) were further studied to investigate their effects at the protein level. Based on the results of an in silico prediction of the protein's functional effect based on amino acid alterations and a sequence conservation evaluation of the amino acid residues at the positions of the nsSNPs among orthologues, we selected one nsSNP in the SQRDL gene (rs1044032, SQRDL I264T) as a meaningful genetic variant associated with postmenopausal osteoporosis. To assess whether the SQRDL I264T variant played a functional role in the pathogenesis of osteoporosis, we examined the in vitro effect of the nsSNP on bone remodeling. Overexpression of the SQRDL I264T variant in the preosteoblast MC3T3-E1 cells significantly increased alkaline phosphatase activity, mineralization, and the mRNA expression of osteoblastogenesis markers, Runx2, Sp7, and Bglap genes, whereas the SQRDL wild type had no effect or a negative effect on osteoblast differentiation. Overexpression of the SQRDL I264T variant did not affect osteoclast differentiation of the primary-cultured monocytes. The known effects of hydrogen sulfide (H2S) on bone remodeling may explain the findings of the current study, which demonstrated the functional role of the H2S-catalyzing enzyme SQRDL I264T variant in osteoblast differentiation. In conclusion, the results of the statistical and experimental analyses indicate that the SQRDL I264T nsSNP may be a significant susceptibility variant for osteoporosis in Korean postmenopausal women that is involved in osteoblast differentiation.

LIN-12/Notch regulates lag-1 and lin-12 expression during anchor cell/ventral uterine precursor cell fate specification.

During Caenorhabditis elegans gonadal development, a stochastic interaction between the LIN-12/Notch receptor and the LAG-2/Delta ligand initiates cell fate specification of two equivalent pre-anchor cell (AC)/pre-ventral uterine (VU) precursor cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expression of lin-12 in VUs and lag-2 in the AC through an unknown feedback mechanism. In this Notch signaling process, the cleaved LIN-12/Notch intracellular domain (NICD) binds to the LAG-1/CSL transcriptional repressor, forming a transcriptional activator complex containing LAG-1 and NICD. Here we show that clustered LAG-1 binding sites in lin-12 and lag-1 are involved in regulating lin-12 and lag-1 expression during AC/VU cell fate specification. Both genes are expressed in VU cells, but not the AC, after specification. We also show that lin-12 is necessary for lag-1 expression in VU cells. Interestingly, lin-12 (null) animals express lag-1 in the AC, suggesting that LIN-12 signaling is necessary for the suppression of lag-1 expression in the AC. Ectopic expression of lag-1 cDNA in the AC causes a defect in the vulvaluterine (V-U) connection; therefore, LAG-1 should be eliminated in the AC to form a normal V-U connection at a later developmental stage in wild-type animals.

Clustered LAG-1 binding sites in lag-1/CSL are involved in regulating lag-1 expression during lin-12/Notch-dependent cell-fate specification.

The cell-fate specification of the anchor cell (AC) and a ventral uterine precursor cell (VU) in Caenorhabditis elegans is initiated by a stochastic interaction between LIN-12/Notch receptor and LAG-2/Delta ligand in two neighboring Z1.ppp and Z4.aaa cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expressions of lin-12 in VU and lag-2 in the AC, through a feedback mechanism of unknown nature. Here we show that the expression pattern of lag-1/CSL, a transcriptional repressor itself that turns into an activator upon binding of the intracellular domain of Notch, overlaps with that of lin-12. Site-directed mutagenesis of LAG-1 binding sites in lag-1 maintains its expression in the AC, and eliminates it in the VU. Thus, AC/VU cell-fate specification appears to involve direct regulation of lag-1 expression by the LAG-1 protein, activating its transcription in VU cells, but repressing it in the AC.