Year : 2008 | Volume
: 26 | Issue : 3 | Page : 121--124
A study of cephalometric appraisal of the inheritance of craniofacial pattern in Gorkhas
OP Mehta1, DS Gupta2,
1 Department of Orthodontics, M.M. College of Dental Sciences and Research, Mullana (Ambala), Haryana, India
2 Department of Orthodontics and Ex-Dean, Faculty of Dental sciences, King George Dental College, Lucknow, India
O P Mehta
Department of Orthodontics, M.M. College of Dental Sciences and Research, Mullana (Ambala), Haryana
The phenotypic expression of biologic variability expressed in the craniofacial complex is influenced by constant interplay of heredity and environmental factors. The aim of this study was to observe the pattern of inheritance of cranio-facial complex in Gorkhas. Gorkhas are the original inhabitants of NEPAL in the slopes of HIMALAYAS and they generally marry strictly in their race. 76 individuals from 19 Gorkha families (son, daughter and both parents); were selected. Eight angular (saddle angle, articular angle, gonial angle, N-S-Gn, N-S-Go, SNA, SNB and ANB angles) and four linear (anterior facial height, posterior facial height, overjet and overbite) variables were measured from lateral head cephalograms and the values of the variables were evaluated and compared. It was found that the Inheritance of cranio facial pattern has shown significant coefficient of correlation from mother to offsprings for jarabak ratio, father to son for NS-Gn and NS-Go angle, father to daughter for articular and ANB angles. Different parts of craniofacial complex represents the resultant of morphology and size variation. Each one of these components are in turn influenced by many genetic and environmental factors.
|How to cite this article:|
Mehta O P, Gupta D S. A study of cephalometric appraisal of the inheritance of craniofacial pattern in Gorkhas.J Indian Soc Pedod Prev Dent 2008;26:121-124
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Mehta O P, Gupta D S. A study of cephalometric appraisal of the inheritance of craniofacial pattern in Gorkhas. J Indian Soc Pedod Prev Dent [serial online] 2008 [cited 2021 Feb 25 ];26:121-124
Available from: https://www.jisppd.com/text.asp?2008/26/3/121/43193
Kniesal  and Charles Delourde  proposed the idea that there is transmission of the pattern of growth of face from parents to offspring and thus a new era of research into the inheritance of the craniofacial complex began. Wylie,  was the first person to use lateral head cephalograms to demonstrate the familial inheritance of traits. Craniofacial characteristics differ with race and geographical location, and any information on these variations can be of great use to the dental professionals during clinical assessment and treatment planning.
The knowledge of craniofacial complex, its structural make-up as well as its growth pattern, is of great significance in the field of clinical dentistry. Although the genes form the blueprint of the craniofacial complex, in the course of growth and development, environmental factors exert their influences, with the result that the phenotype shows new characteristics. , Genetic factors have been shown to exert greater influence on the final form of the individual than environmental factors.
Therefore, a child may have facial features that resemble one or both the parents and, also, siblings may show a great resemblance to one another.  The constant interplay of heredity and environmental factors is responsible for the phenotypic expression of the biologic variability observed in the craniofacial complex. 
Gorkhas are short-statured, square-faced and of stocky build, with a striking resemblance to one another; Gorkhas are the original inhabitants of Nepal, a country situated on the slopes of the Himalayas. They generally marry within their own race. Hence, to study the inheritance of the craniofacial pattern and sexual dimorphism of this race.
Materials and Methods
The study was based on 76 individuals from 19 Gorkha families consisting of son, daughter and both the parents with known history of marital relationships in the same race. The children were selected between the age group of 7 years to 18 years with no past history of any orthodontic treatment.
Lateral head cephalograms with teeth in occlusion were taken of each member of the selected family.
The films were developed and traced as per the standard procedure.
The landmarks and planes used in this study were: sella, nasion, point A, point B, pogonion, gnathion, menton, gonion, and articulare. The reference planes used were: S-N plane, S-Ar plane, Ar-Go plane, Go-Me plane, N-A plane, N-B plane, S-Gn plane, and S-Go plane [Figure 1] and [Figure 2].
Eight angular and four linear measurements were selected on the lateral cephalograms. The angular measurements were saddle angle, articular angle, and gonial angle of Bjork; 
NS-Gn angle of Brodie;  N-S-Go angle of Wylie;  and S-N-A, S-N-B, and A-N-B angles of Riedal (1952). The linear measurements were N-Me (total anterior facial height), S-Go (posterior facial height), and Jarabak ratio was calculated; overjet and overbite were measured as per the standard procedure.
The present study was conducted on 76 individuals of 19 Gorkha families. The individuals were grouped under four different headings: father, mother, son, and daughter.
The age of the father ranged between 31-49 years with the mean age of 40.2 years. The age of the mother ranged between 28-45 years and the mean age was 37.5 years. The mean ages of sons and daughters were 12.1 years and 10.8 years, respectively, with a range of 7-18 years.
To evaluate the comparative values of the variables the results were tabulated under the headings of range, mean, standard deviation, and coefficient of variation for all the cephalometric variables of father, mother, son, and daughter.
The product-moment correlation coefficients were calculated to determine the extent of relationships in the measurements of all the cephalometric variables between father-son, father- daughter, mother-son, mother-daughter, and son-daughter combinations and the values were tabulated [Table 1].
The present study was undertaken to ascertain the possible mode of inheritance of the craniofacial pattern among Gorkhas. Brodie  has demonstrated that the facial pattern of the individual does not change after the third month of life and age does not significantly affect the magnitude of the angles. Nakata  suggested that the age of the offspring was a strong predictor variable for linear measurements.
In the present cephalometric study, eight angular and four linear measurements were taken in addition to the Angle's class 1 molar relationship.
There was significant correlation between father and offspring with regard to the saddle angle, whereas the correlation was nonsignificant between mother and offspring, indicating that the possible mode of inheritance is from father to the offspring. Ohno et al .,  in a study on 17 North Indian families, in which the minimum age of the offspring was 17 years, showed significant correlation among the siblings and also in the mother-son combination. This difference from our findings is probably because they studied a different race and also because of the older ages of the offspring in their study.
For the articular angle there was a highly significant correlation between father and daughter, whereas the correlation was nonsignificant in the father-son and mother-offspring relationship, indicating that this variable was predominantly transmitted from father to daughter. Ohno et al .,  however, reported that the correlation between fathers and daughters was not significant. This difference may be due to racial variations and incomplete growth of the craniofacial complex. However, dominant mode of inheritance from father to daughter has been observed in this present study it needs further confirmation in a larger group of individuals, with the same strict criteria of sample selection as used in this study.
The gonial angle showed significant correlation between father and daughter in this study, which coinsides with the findings of Porado et al .  and Ohno et al .  but it does not coinside with the findings of Nakata et al .  and Sood et al . 
The NS-Gn angle showed significant correlation between father and son and father and daughter, indicating the strong possibility of inheritance of this factor from father to offspring as observed by Harris et al ,  in his study on genetic factors in the shape of craniofacial complex.
There was highly significant correlation for this angle in the father-son combinations. Wylie  in 1944 used the NS-Go angle to show the position of the Gonion anteroposteriorly. The coefficient of correlation between son and daughter was also significant. These findings are in conformity with the findings of Dudas and Sassouni  who showed a strong genetic component in NS- Go angle.
The SNA angle showed significant coefficient of correlation between mother and offspring, whereas the correlation between father and offspring was nonsignificant, therefore it should be studied in a larger sample than in this study as nonsignificant values have also been seen by Sabhlok et al . 
A significant coefficient of correlation was exhibited between father and offspring for the SNB angle, indicating the positive mode of inheritance from father to both male and female offspring. Sabhlok et al .  obtained the same findings but, again, a larger sample is required to confirm these findings. Hunter et al .,  Nakata et al .,  and Sood et al .  have shown the dominant influence of the father on the offspring for mandibular growth.
For the ANB angle there is significant correlation between father and daughter, which was not seen for the other combinations. This needs further confirmation with a larger sample. In this study SNA angle has significant coefficient coorelation from mother to offspring and SNB from father to offspring. Harris etal in 1975 has reported that angle ANB represents the resultant of morphology and size variations in various components of craniofacial complex (mainly nasomaxilliary complex and mandible) and each of these components are in turn, influenced by there own genetic mode of inheritance and influenced by environmental factors during growth and development of craniofacial complex.
Jarabak ratio has shown very significant coefficient of correlation between mother and offspring but there is nonsignificant correlation between father and offspring. There has been strong correlation among siblings, indicating the possibilities of sexual dimorphism among brothers and sisters.
Overjet showed significant coefficient of correlation for all the groups except among siblings, possibly indicating a positive mode of inheritance from the both the parents to offspring. The findings of this study, however, do not correlate with the findings of Karia et al .  and Nakasima et al . 
Overbite showed significant correlation in the mother-son combination but not in the other groups in this study. The findings of this study do not agree with the findings of Karia et al .  and Nakasima et al .  However, Nakasima et al .  found that the deeper the bite of the parents, the deeper was the bite of the progeny.
Articular angle and ANB angle have a dominant mode of inheritance from father to daughter; NS-Gn angle and NS-Go angle have a dominant mode of inheritance from father to son.Facial height has a dominant mode of inheritance from mother to offspring.Overbite has a dominant mode of inheritance from mother to son.
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