Description of Clinical Facial Analysis of Down Syndrome Patients Using Rhinobase Software: An Anthropometric Study

Abstract

Introduction: Patients with Down syndrome have distinctive facial characteristics. Physical abnormalities that have many similarities make people with Down syndrome very similar to each other. This study aimed to determine the clinical facial analysis of patients with Down syndrome using Rhinobase Software. Methods: A descriptive observational study was conducted on patients with Down syndrome aged 10–29 years who met the criteria. Data were obtained through history taking, general facial physical examination and ENT-HN examination. Facial analysis using Rhinobase software. Result: The results obtained were analyzed using the SPSS program. The average age of the sample was 17.7 ± 4.8 years with 73% of the sample being male. In the vertical facial assessment, the proportion of LFH > UFH > MFH was obtained. In the horizontal face assessment, 96% of the samples have En-En < Al-Al ratios. The proportion of the lower face height of people with Down syndrome to the whole face is greater than the proportion of the upper and middle height of the face. Conclusion: The value of the intercanthal distance is greater than the mean ideal intercanthal distance, and the highest proportion was the intercanthal distance which was smaller than the width of the ala nasi.

Introduction

Down syndrome (DS) is a genetic disorder that causes intellectual disability, distinctive facial characteristic and an increased risk of other organ disorders caused by trisomy 21 [1]. The incidence of DS is estimated to be 1/1000 to 1/1,100 live births worldwide. Every year about 3,000 to 5,000 children are born with Down syndrome and it is believed that there are about 250,000 families in the United States affected by Down syndrome [2].

Down syndrome is a disorder known as a genetic disorder caused by the presence of three chromosomes 21 [3]. The presence of additional chromosome 21 (HSA21) in DS causes overexpression of 30–50% of the HSA21 gene. This upregulation may trigger deregulation in non-HSA21 gene expression [4]. Gene dose imbalance on chromosome 21 (HSA21) affects complex gene regulatory interactions and alters development resulting in a variety of phenotypes, including the facial dysmorphology characteristic of Down syndrome [5].

Physical abnormalities that have many similarities make DS patients very similar to each other. This disorder is easily recognized in almost all parts of the body with different frequencies. Physical abnormalities that can be found in almost all age groups of DS patients are small head size (microcephaly) with a flat area at the nape of the neck, wide intercanthal distance, flat face caused by small cheekbones and nasal bones, large tongue, simian lines, and short fingers. In DS patients, other abnormalities can be found such as abnormalities in the eyes, ears, respiratory tract, heart and immunological system [6].

Ferrario and Dellavia, in their study of 28 DS patients aged 12–45 years, concluded that overall variables in DS were different from normal controls based on sex, age, and ethnicity. Patients with DS have a narrower face, shallower both the upper, middle and lower faces. The height of the face and nose is shorter, furthermore, the length and width of the ears are decreased. The wide intercanthal distance in DS patients has created a negative stigma for DS patients [7].

The dependency of people with Down’s syndrome should be reduced, especially those who have a subnormal IQ. Efforts are needed to reduce the stigma associated with facial abnormalities in DS patients. Chromosomal therapy and/or gene therapy in humans have many practical and ethical difficulties. However, genetic correction in the early stages of prenatal development in DS may be possible in the future. Its main target is the correction of embryonic genes that induce the normalization of gene expression in most body cells [8]. Another effort that can be done at this time is with facial correction. To correct the facial deformity, additional surgery is needed to fix the shape of the abnormality. Before taking corrective actions for facial deformities, clinical analysis of the face is required. Clinical facial analysis (CFA) is a method doctors use to evaluate and assess a patient’s face, to determine proportion, volume, appearance, symmetry, and deformity. This is obtained from physical examination, clinical photos, as well as conventional and computerized x-ray imaging [9].

Rhinobase software is a program to analyze the face using photogrammetric as the medium. Rhinobase provides evidence of high reliability for several nasofacial measurements. The nasofacial analysis allows accurate preoperative evaluation, surgical planning, and analysis of outcomes in rhinoplasty, and it can be a useful tool for both novice and experienced rhinoplasty surgeons [10]. Clinical analysis of the face is very important for some specialists, such as ENT specialists and plastic surgeons who deal with facial aesthetics and function [9].

To reduce the stigma associated with facial abnormalities in DS patients, this study aimed to find out the anthropometric characteristic values of the DS face. The finding of this study can be considered for further research to obtain reference values for facial parameters that can be used for facial reconstruction in DS.

Materials and Methods

Research Design

This was a descriptive observational study. The study was conducted from July 2021 to July 2022 at the several Special School in Padang City. The number of samples was 26 people who were taken by purposive sampling. The study sample was Down’s syndrome patients who had been confirmed by chromosomal analysis as having trisomy 21, aged 10–29 years, have never had facial surgery or facial trauma before, were not undergoing orthodontic treatment, and did not have complex craniofacial disorders.

After obtaining written consent from the school principal, data were collected on children diagnosed with Down syndrome. If the sample meets the criteria, then it is selected as the research sample. Samples and parents were given information about the research and then parents were asked to fill out and sign a research consent form. This research was approved by Ethical Committee of Research, Faculty of Medicine, Andalas University, with approval number 578/UN.16.2/KEP-FK/2021.

Collection Data

Data were obtained through history taking, general facial physical examination, and ENT-HN examination. Then, the anthropometric points of the face were marked with markers and the face was photographed in 3 positions a.i, frontal, lateral, and basal positions.

Data Analyis

The photos were processed using Rhinobase software.

Statistical Analysis

All data were analyzed using the SPSS program.

Limitation

This study was conducted to determine the clinical facial analysis of Down syndrome patients. The limitations of this study are this study just provides basic anthropometric characteristic values of the Down syndrome face. Further research is needed regarding the most striking and most frequent differences in Down syndrome when compared to normal facial characteristics according to certain ethnicities so that what parameters will be reconstructed can be identified. This research could provide reference points in the facial reconstruction of Down syndrome patients but still needs further research to get a satisfactory surgical result.

Results and Discussion

Result

Characteristics of Subject

The distribution of most subjects by gender was male, i.e. 73%, while the female was 27%. Based on age, the three age groups were equal in number, a.i. 31% respectively, while the 25–29 age group was only 7% (Table 1).

Table 1.

Distribution of subject characteristics based on age and sex

Characteristics	F	%
Gender
Male	19	73%
Female	7	27%
Age
10–14	8	31%
15–19	8	31%
20–24	8	31%
25–29	2	7%

Based on facial clinical analysis using Rhinobase Software, 21 parameters were analyzed on 26 facial samples of people with Down’s syndrome, in Table 2.

Table 2.

Distribution of facial anthropometric parameters of patients with Down’s syndrome

No	Parameters	Mean	Min	Max	Std Dev
1	UFH (mm)	60.86	40.1	79.6	9.78
2	MFH (mm)	61.01	52.3	73.2	6.26
3	LFH (mm)	67.61	47.2	84.4	9.38
4	ULL (mm)	12.93	6.6	20	3.25
5	SM (mm)	45.63	30.2	57.6	6.77
6	En-En (mm)	37.42	30	42.9	3.02
7	Mf-Mf (mm)	16.19	10.6	20.4	2.30
8	Al-Al (mm)	43.30	33.9	49.8	3.64
9	NFA (o)	132.85	119	143	6.09
10	NFcA (o)	31.93	25.5	41.5	4.02
11	NLA (o)	109.32	85.3	145	16.37
12	MCA (o)	110.96	101	126	6.09
13	NMA (o)	137.15	129	151	5.67
14	Angle of Curvature of the Face (o)	9.35	0	17	4.54
15	NT (mm)	32.91	26.9	37.5	2.97
16	Sn-C (mm)	8.23	4.5	13.3	2.05
17	Simons Tip Projection	0.66	0.3	0.9	0.14
18	Powell-Modified Baum Tip Projection	3.75	2.3	4.9	0.59
19	Collumella Show (mm)	6.59	2.8	9.5	1.67
20	Mentolabial Sulcus (mm)	3.11	0.2	7.1	1.48
21	Lobul-Basal Comparison	0.58	0.32	0.86	0.14

Note: Upper Facial Height (UFH), Middle Facial Height (MFH), and Lower Facial Height (LFH)

Based on the above parameters, the largest standard deviation value for the NLA parameter is 16.37 with an average of 109.32, a minimum value of 85.30 and a maximum value of 145.00. The smallest standard deviation value is found in Simons’s nasal tip projection parameter, which is 0.14 with an average of 0.58, a minimum value of 0.32 and a maximum value of 0.86.

Vertical Facial Assessment

The vertical face assessment according to the Neoclassical Canons is divided into three equal parts (Horizontal Third), i.e. Upper Facial Height (UFH), Middle Facial Height (MFH), and Lower Facial Height (LFH). Based on Table 2, the average value of Upper Facial Height (UFH) is 59.14, Middle Facial Height (MFH) is 57.76, and Lower Facial Height (LFH) is 65.38.

Table 3 shows that 13 samples (50%) had a higher proportion of upper-facial height than the proportion of middle facial height. The upper facial height proportion is smaller than the lower facial height proportion found in 15 samples (58%). Most of the samples (73%) had a lower proportion of middle facial height compared to lower-facial height proportions.

Table 3.

Vertical distribution of facial height

Face Height	f	%
UFH = MFH = LFH	0	0%
UFH = MFH	0	0%
UFH > MFH	13	50%
UFH < MFH	13	50%
UFH = LFH	1	4%
UFH > LFH	10	38%
UFH < LFH	15	58%
MFH = LFH	0	0%
MFH > LFH	7	27%
MFH < LFH	19	73%

Note: Upper Facial Height (UFH), Middle Facial Height (MFH), and Lower Facial Height (LFH)

Based on Table 4, the data obtained that the proportion of lower facial height to the whole face is greater than the proportion of the upper facial and middle facial height of the face, with a proportion of 35.68%.

Table 4.

Facial vertical proportion

Parameters	Proportion
Upper Facial Height (UFH)	32.12%
Middle Facial Height (MFH)	32.20%
Lower Facial Height (LFH)	35.68%
Total	100%

Horizontal Facial Assessment

The horizontal facial assessment according to the Neoclassical Canons is divided into five (Vertical Fifths), thus the values for the width of the eyes, the distance of the epicanthal, and the width of the Ala Nasi are the same. Parameters that can be assessed in this study are epicanthal distance (En-En), nasal floor width (Mf-Mf) and Ala Nasi width (Al-Al). Based on Table 2, the average value of the intercanthal distance (En-En) is 36.92, the nasal floor width (Mf-Mf) is 15.45, and the width of Ala Nasi (Al-Al) is 41.93.

Based on Table 5, it was found that all the samples had a smaller ratio of the intercanthal width than the Ala Nasi width.

Table 5.

Comparison distribution of epicanthal distance with the Ala Nasi width

Parameter	f	%
En-En = Al-Al	0	0%
En-En > Al-Al	0	0%
En-En < Al-Al	26	100%

Nasal Analysis

Parameters that can be assessed for nasal analysis are nasal length (NT), total facial length (UFH + MFH + LFH), the width of Ala Nasi (Al-Al), columella length (Sn-C), Nasal tip projection, Collumella show and the ratio of the lobule nasal width to the nasal base. Based on Table 2, the average nasal length (NT) in patients with Down’s syndrome is 32.91. The mean distance between the subnasal (sn) and the columella breakpoint (Sn-C) is 8.23. The mean Simons Tip Projection distance which is the ratio of the superior Subnasal-vermilion distance to the Nasi-Subnasal Tip is 0.66. The mean distance of the Powell Tip projection which is the ratio between the Nasion-Subnasal and the perpendicular line passing through the apex of the nose is 3.75. The mean Columella Show was 6.59 and the mean lobule-basal ratio is 0.58.

Facial Aesthetic Angle

In this study, there are several parameters for evaluating facial aesthetic angles, including the Nasofrontal Angle (NFA), Nasofacial Angle (NFcA), Nasolabial Angle (NLA), Nasomental Angle (NMA), and Mentocervical Angle (MCA). Based on the facial aesthetic angle parameters in Table 2, the mean value of NFA is 132.85^o, NFcA 31.93^o, NLA 109.32^o, NMA 137.15^o, and MCA 110.96^o.

Discussion

This study aims to obtain data on the facial characteristics of people with Down’s syndrome. The study was conducted on 26 samples consisting of 19 male samples and 7 female samples (Table 1). The age distribution of the sample was divided into four groups with three age groups of 8 people each, a.i. the age group of 10–14 years, 15–19 years, and 25–29 years.

Based on the vertical facial assessment, the mean upper facial height (UFH) was 60.86 mm, the middle facial height (MFH) was 61.01 mm, and the lower facial height (LFH) was 67.61 mm with an average total facial height of 189.48 mm (Table 2). The proportion of the lower facial height of people with Down’s syndrome to the whole face is greater than the proportion of the upper facial and middle facial height with LFH > MFH > UFH values. In Down’s syndrome, developmental disorders occur in almost all parts of the body, including the development of the facial bones. In this syndrome, there is a narrowing of the nasal and maxillary tubes and the appearance of a small chin (micrognathia) which gives this syndrome a characteristic appearance with a flat face and short facial height [6, 11].

A study conducted by Koento found significant differences in the mean facial width and height between Down syndrome patients and controls [12]. Meanwhile, a study conducted by Farkas and Munro focused on the head and facial features that are most frequently described in the literature on Down syndrome. From the results of their study on 52 Down syndrome patients, it was found that the measurements with the most subnormal results were located in the head area, head circumference (59.6%), on the face, i.e. the depth of the upper 1/3 of the face (71.5%), and eyes with a long palpebral fissure (68.8%). Hafiz conducted a study to determine the facial characteristics of the normal Minangkabau ethnic group. His study obtained a mean total facial height is 238.02 mm for male samples and 228.50 mm for female samples. This value is greater than the mean total facial height of patients with Down syndrome in this study (182.28) [13].

In horizontal facial assessment, the parameters assessed were epicanthal distance (En-En), nasal floor width (Mf-Mf) and the Ala Nasi width (Al-Al) (Table 4). In this study, the mean value of the intercanthal distance (En-En) was 37.42 mm, the nasal floor width (Mf-Mf) was 16.19 mm, and the width of Ala Nasi (Al-Al) was 43.30 mm. One of the distinctive facial characteristics of Down’s syndrome is the wide intercanthal distance. In patients with Down’s syndrome, there was a statistically significant increase in the mean value of the intercanthal distance compared to controls. A study conducted by Koento found difference of 3.87 mm in the intercanthal distance of Down’s syndrome and control. The intercanthal distance of Down’s syndrome was greater than the control [12]. Ideally, the intercanthal distance should be half the interpupillary distance. The intercanthal distance should also be equal to the width of the ala at the base of the Caucasian nose. The average intercanthal distance is 30–35 mm and the average interpupillary distance is 60–70 mm [9, 14]. In this study, it was found that the value of the intercanthal distance of Down’s syndrome was greater than the average ideal intercanthal distance.

The distribution of the ratio of the intercanthal distance to the width of the ala nasi showed that all sample had a smaller intercanthal distance than the width of the ala nasi. The typical features of the Asian nasal are a broad and low dorsum, a defined tip projection, broad lobules, thick lobulated skin, subcutaneous fat tissue, and columella retraction [9, 14]. The results in this study are different when compared to the normal values of facial anthropometry based on the Caucasian race, a.i. the intercanthal distance is the same as the width of the ala nasi [15].

On the nasal parameter, the mean nasal length (NT) in Down syndrome patients is 32.91 mm. The nasal length of people with Down’s syndrome is shorter than the nasal length of the normal group in Hafiz’s study [13]. The nose is one of the most visually characteristic areas of Down syndrome patients, a.i. visually a flat and short nose can be seen due to the narrowing of the nasal bone [12].

According to Powell and Humphrey, quoted by Sim and Thorium, facial aesthetic angles have ideal values, a.i. the nasofrontal angle (NFA) of 115⁰-130⁰, the Nasofacial angle (NFcA) of 30⁰-40⁰, the Nasomental angle (NMA) of 120⁰-132⁰, the Mentocervical angle (MCA) of 80⁰-95⁰ and also Nasolabial angle (NLA) of 90⁰-120⁰[16]. Patients with Down syndrome in this study had NFA, NMA and MCA angle values greater than the ideal value. The NFcA and NLA angle values are still in the ideal range. When compared with the study of Hafiz et al. in the normal Minangkabau ethnic group, the NLA, NMA and MCA angle values in Down’s syndrome are greater.

Conclusions

This study found that on a vertical facial assessment, the proportion of the lower facial height of people with Down syndrome compared to the whole face was greater than the proportion of the upper and middle facial height. In the horizontal facial assessment, the value of the intercanthal distance is greater than the average ideal intercanthal distance with the highest ratio, a.i, the intercanthal distance is smaller than the width of the ala nasi. However, this study was limited to patients in a specific area. Larger samples are necessary to be further analyzed. This study will be a guide for further study.

Author Contributions

Conceptualization, A.H. and A.; methodology, A.H.; software, A.H.; vali-dation, Y. and T.; formal analysis, A.; investigation, Y.; resources, T.; data curation, A.; writ-ing—original draft preparation, A.H.; writing—review and editing, A., Y. and T.; visualization, A.H. All authors have read and agreed to the published version of the manuscript.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data Availability

Not applicable.

Declarations

Institutional Review Board Statement

Ethical approval for this study was obtained from the Committee of Research Ethics, Faculty of Medicine, Andalas University, with approval number 578/UN.16.2/KEP-FK/2021.

Informed Consent

Written informed consent has been obtained from the patient(s) to publish this paper.

Conflict of Interest

The authors declare no conflict of interest.