• The korean journal of orthodontics
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• v.49 no.1
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• pp.3-11
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• 2019

Objective: The purpose of this study was to investigate the influence of heritability on the craniofacial soft tissue cephalometric characteristics of monozygotic (MZ) twins, dizygotic (DZ) twins, and their siblings (SIB). Methods: The samples comprised Korean adult twins and their siblings (mean age, 39.8 years; MZ group, n = 36 pairs; DZ group, n = 13 pairs of the same gender; and SIB group, n = 26 pairs of the same gender). Thirty cephalometric variables were measured to characterize facial profile, facial height, soft-tissue thickness, and projection of nose and lip. Falconer's method was used to calculate heritability (low heritability, $h^2$ < 0.2; high heritability, $h^2$ > 0.9). After principal components analysis (PCA) was performed to extract the models, we calculated the intraclass correlation coefficient (ICC) value and heritability of each component. Results: The MZ group exhibited higher ICC values for all cephalometric variables than DZ and SIB groups. Among cephalometric variables, the highest ${h^2}_{(MZ-DZ)}$ and ${h^2}_{(MZ-SIB)}$ values were observed for the nasolabial angle (NLA, 1.544 and 2.036), chin angle (1.342 and 1.112), soft tissue chin thickness (2.872 and 1.226), and upper lip thickness ratio (1.592 and 1.026). PCA derived eight components with 84.5% of a cumulative explanation. The components that exhibited higher values of ${h^2}_{(MZ-DZ)}$ and ${h^2}_{(MZ-SIB)}$ were PCA2, which includes facial convexity, NLA, and nose projection (1.026 and 0.972), and PCA7, which includes chin angle and soft tissue chin thickness (2.107 and 1.169). Conclusions: The nose and soft tissue chin were more influenced by genetic factors than other soft tissues.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.21 no.3
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• pp.133-140
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• 2010

Tic disorders, including Tourette syndrome, are known as neurobiologic disorders and as such, much emphasis has been placed on isolating genetic determinants. Although previous reports involving studies of discordance among monozygotic twins have shown the importance of genetic predisposition, they have also supported a role for environmental factors in the development of tic disorders. Therefore, it is important to consider that both genetic and environmental factors contribute to their clinical expression. The goal of this article was to review recent reports regarding the role of environmental factors in development and progression of tics. Specific environmental factors associated either with a more severe course of illness or improved outcomes were discussed. Given that accumulating evidence had suggested the usefulness of behavior therapies in the suppression of tic disorders, particular emphasis was placed on the impact of several contextual factors.

• 대한생식의학회:학술대회논문집
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• 2007.11a
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• pp.143-144
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• 2007

• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.157-163
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• 2014

Respiratory distress syndrome (RDS) among preterm infants is typically due to a quantitative deficiency of pulmonary surfactant. Aside from the degree of prematurity, diverse environmental and genetic factors can affect the development of RDS. The variance of the risk of RDS in various races/ethnicities or monozygotic/dizygotic twins has suggested genetic influences on this disorder. So far, several specific mutations in genes encoding surfactant-associated molecules have confirmed this. Specific genetic variants contributing to the regulation of pulmonary development, its structure and function, or the inflammatory response could be candidate risk factors for the development of RDS. This review summarizes the background that suggests the genetic predisposition of RDS, the identified mutations, and candidate genetic polymorphisms of pulmonary surfactant proteins associated with RDS.

• Korean Journal of Animal Reproduction
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• v.12 no.3
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• pp.132-140
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• 1988

These experiments were carried out to examine the development capacity of mouse blastomers separated from 2 to 8-cell stage mouse embryos. The female ICR and C3H mice were subjected to supervolution by intraperitoneal injection of PMSG and HCG and then mated with males of the same strain. Embryos were flushed from oviducts and uteri on a proper time after injection of HCG. After removal of zona pellucida with 0.5% pronase, each embryos were separated into 1/2, 1/4, 2/4, 1/8, 2/8 and 4/8 embryos by pipetting or a fine glass needle in Ca2＋$.$Mg-2＋ free Hoppe& Pitts medium containing 0.02% EDTA. Splitted embryos were cultured in Hoppe & Pitts medium for 48h to 72h. The embryos developed to blastocyst were transferred to recipients on 2 or 3 days of pseudopregnancy. On the other hand, a monozygotic pairs of 1/2 embryos developed to blastocyst after 48h in vitro culture were transferred to recipients on 2 days of pseudopregnancy or pregnancy. The results obtained were summarized as follows. 1. Success rates of separation of blastomeres from 2-, 4- and 8-cell embryos were 91.7%, 68.5-92.4% and 60.8-90.6%, respectively. 2. Development rates of various type of blastomeres to blastocyst after 72h in vitro culture were ranged 64.7-87.1%. 3. Blastocysts obtained after 48h in vitro culture were transferred to recipients on 2 or 3 days of pseudopregnancy. The production rates of live fetuses after transfer on 2 days, only 1/2, 2/4 and 4/8 embryos, were 13.2%, 13.5% and 17.2%, respectively and those of embryos transferred on 3 days were 11.8%, 9.6% and 11.5%, respectively. However, the production rates of live fetuses 1/2 embryos following 72h in vitro culture and transfer to recipients on 2 or 3 days of pseudopregnancy were 7.7% and 12.5%, respectively. 4. From 29 and 31 pairs of 1/2 embryos transferred to recipients on 2 days of pseudopregnancy or pregnancy, 4 sets of monozygotic twins were produced from only pregnant recipients.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.370-377
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• 2017

Molar-incisor malformation (MIM) is a recently described dental anomaly characterized by root malformation in permanent first molars accompanied sometimes by abnormal root forms in primary second molars or enamel defects in maxillary central incisors. This report presents three cases of MIM along with a review of previous studies. Three patients exhibited abnormal root forms in the permanent first molars, with varying degrees of deformation. Two of the patients experienced medical events at birth. One of the patients was a monozygotic twin, whose twin sister exhibited normal dentition without any significant abnormalities. The present report also reviews recently reported cases of MIM in literature. In the management of MIM-associated clinical issues, consideration of microscopic features and accompanying characteristics might facilitate early diagnosis and comprehensive treatment planning.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.1
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• pp.1-12
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• 2010

This research was intended to delve into the diversity of life phenomenon and its characteristics. First of all, this research gave real examples to compare the differences in men's health, disease, and longevity in order to confirm the existence of diversity of life phenomenon. In addition, it also studied the process and mechanism of manifestation of life phenomenon, as well as the influence and problems of existing studies' results and implications. The results are as follow. 1. Differences in health, diseases, and longevity were very big and diverse in researches on different races, nations, ages, socioeconomic status, positions, and even (monozygotic) twins. 2. The basic foundation of all organisms is DNA, and environmental factors change DNA methylation and the structure of chromatin by constantly influencing DNA. Due to this, the manifestation, control, and phenotype of DNA change, resulting in diversified life phenomenon. Therefore, it is the environmental factors, not DNA, that has more influence on the diversity of life. 3. Looking at available studies, the most reasonable perspective on human requires focusing on the diversity of life phenomenon, holistic thinking, and reversible change instead of irreversible determinism. Considerable differences in life phenomenon between entities require a change in malformed perspective on life. Public health and medicine deals with live human beings, a more precise and accurate perspective on life is very important. Because management methods of health and disease, such as structure and approaches of medical research, prevention and cure, must be different by life perspectives.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.2
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• pp.1-12
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• 2010

The individual differences in disease development and susceptibility have been researched primarily on the subject of genes, environment or the interaction between genes and the environment respectively. However, there have been limitations in explaining complex diseases, and the differences in health and diseases in monozygotic and dizygotic twins. Fortunately, thanks to active research on the relationship between genes and the environment, and epigenetics, there has been much progress in the understanding of body's reactions and changes. Epigenetics is referred to as a study of gene expression through the interactions of DNA methylation, chromatin's histone and the change of structure in tail, RNA editing without any change in DNA sequence. In this paper, we introduce the basic concepts and mechanisms of epigenetics. The result of the epigenetics is heritable ; can regulate gene expressions ; is reversible ; and has many variable forms depending on cell types. The influences of epigenetics occur throughout life, but it is mainly determined in utero during early pregnancies. Diseases occur or the risk rises if these influences continue after birth until adult life when problems occur in excess/lack of nutrition, environmental plasticity, or already inputted data. Therefore, there is a need for change and innovation, especially in interest and investment in health education for young women near pregnancies and correct treatment of epigenetic-related diseases.

• Advances in pediatric surgery
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• v.1 no.1
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• pp.8-17
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• 1995

The clinical experience of 2,340 inguinal hernia repaired by one pediatric surgeon on 2,079 children at Hanyang University Hospital from September 1979 to December 1993 was analyzed. Of 2,046 patients who had primary hernia repairs at Hanyang University Hospital, 1,636 were male and 410 female, and 55.5% of hernias occurred on the right side, 36.0% on the left, and 8.6% were bilateral. The patients presented hernia under the age of 12 months were 45.3% and those performed herniotomy under the age of 12 months were 25.5%. Birth weight was less than 2.5kg in 111 patients(8.7%) of 1,279 data available patients. Ninety(6.6%) of 1,354 data available patients were premature(<37wks gestation). The proportions of bilateral inguinal hernia and the onset age under 12 months of life in low birth weight babies and premature babies were higher than in full-term babies. Incarcerated inguinal hernia occurred in 327 patients(16.0%) of whom 8 patients were strangulated hernias. The occurrence of incarceration inversely related with age of patients. The subsequent contralateral inguinal hernia following unilateral hernia repairs occurred in 80 patients(4.3%) among which 72 were male and 8 were female. The incidence of contralateral inguinal hernia was more frequent in boys(4.8%) than girls (2.2%) and in cases after left herniotomy(6.4%) than after right herniotomy(2.9%). Sixty percent of contralateral inguinal hernia developed within 1 year after primary hernia repair. The recurrence of inguinal hernia occurred in 6 patients(0.27%) treated at our hospital primarily. There were one or more associated congenital anomalies in 83 patients of which congenital heart diseases were the most common. Sliding hernia occurred in 25 patients consisted of 5 boys and 20 girls. Family history was noted in 35 patients and there were 28 sets of monozygotic and 3 sets of dizygotic twins.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.407-418
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• 2021

Objective: To investigate differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and Class II malocclusions. Methods: Forty Korean adult twin pairs were divided into Class I (C-I) group (0° ≤ angle between point A, nasion, and point B [ANB]) ≤ 4°; mean age, 40.7 years) and Class II (C-II) group (ANB > 4°; mean age, 43.0 years). Each group comprised 14 monozygotic and 6 dizygotic twin pairs. Thirty-three cephalometric variables were measured using lateral cephalograms and were categorized as the anteroposterior, vertical, dental, mandible, and cranial base characteristics. The ACE model was used to calculate heritability (A > 0.7, high heritability). Thereafter, principal component analysis (PCA) was performed. Results: Twin pairs in C-I group exhibited high heritability values in the facial anteroposterior characteristics, inclination of the maxillary and mandibular incisors, mandibular body length, and cranial base angles. Twin pairs in C-II group showed high heritability values in vertical facial height, ramus height, effective mandibular length, and cranial base length. PCA extracted eight components with 88.3% in the C-I group and seven components with 91.0% cumulative explanation in the C-II group. Conclusions: Differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and II malocclusions might provide valuable information for growth prediction and treatment planning.