|Year : 2017 | Volume
| Issue : 1 | Page : 52-54
Karyotype analysis for Turner syndrome
HS Vanishree1, Shobha Bijjaraji2, Anand S Tegginamani1
1 Faculty of Dentistry, SEGi University, Kota Damansara, Malaysia
2 Department of Oral Medicine and Radiology, MIDSR Dental College, Latur, Maharashtra, India
|Date of Web Publication||30-Jun-2017|
H S Vanishree
Faculty of Dentistry, SEGi University, Kota Damansara
Source of Support: None, Conflict of Interest: None
The first karyotype investigation in a patient with Turner syndrome (TS) was performed in England, in 1959; prior to that, it was thought that humans possessed 48 chromosomes. Most individuals with down-syndrome possess 47 chromosomes, with an extra copy of chromosome 21. Most individuals with TS possess 45 chromosomes, with a missing X chromosome. Here, we present 45 XO karyotype analysis in a 12-year-old girl with TS; although it is common in females, it is still rare to encounter in dental institutions. Oral physicians and pediatric dentists need to be aware of the major clinical features for definitive diagnosis of TS for early recognition and timely investigation which will improve their quality of life and to guide for the oral care.
Keywords: Chromosomal disorder; karyotype; Turner syndrome
|How to cite this article:|
Vanishree H S, Bijjaraji S, Tegginamani AS. Karyotype analysis for Turner syndrome. Indian J Multidiscip Dent 2017;7:52-4
| Introduction|| |
Turner syndrome (TS) is a relatively common chromosomal disorder caused by complete or partial X monosomy. TS is one of the most common types of aneuploidy in humans, and is present in 1:2000 newborns with female phenotype. The first karyotype investigation in a patient with TS was performed in England, in 1959, by Ford et al. to describe X-chromosome monosomy, i.e., the 45, X karyotype, which is the type most frequently found among patients with TS. Today, TS is a clinical challenge for its genetic-, developmental-, endocrine-, cardiovascular-, psychosocial-, and reproductive-related problems. Prenatal suspicion of TS is made when ultrasonography shows increased nuclear translucency, presence of cystic hygromas, coarctation of aorta, brachycephaly, renal anomalies, polyhydramnios, or growth retardation. Before terminating pregnancies in suspected TS, counseling should be done to the family explaining its broad clinical spectrum possibility of short stature and management of ovarian failure and overall management protocol rather than giving a gloomy picture and a hurried decision of terminating the pregnancy. Postnatal diagnosis of TS is confirmed by karyotype test in all individuals with suspected TS. Here, we present 45 XO karyotype analysis in a female with TS; although it is common in females, it is rare to encounter in dental outpatient departments.
| Case Report|| |
A 12-year-old female reported to the dental outpatient department with the chief complaint of forwardly placed upper front teeth, for 2 years. Parents noticed the forwardly placed teeth since 2 years and gave a history of full-term delivery, uneventful, and had a birth weight of 2.1 kg with delayed milestones. Physical examination revealed short stature with a height of 114 cm and weight of 20 kg associated with microcephaly, broad chest [Figure 1], low hair line, low set ears, small fingernails, and also downturned movement of the mouth. She underwent ophthalmic assessment in a private eye clinic where she was found to have squint eyes and also downturned movement of the eyes. No other abnormality was detected. Oral examination revealed high-arched palate [Figure 1]a and concave profile with incompetent lips, Angle's class II molar relationship bilaterally with increased overjet of about 6 mm and overbite of about 3–4 mm. Orthopantomograph (OPG) showed no change in the bone density, extracted socket in relation to 36, 46 deep proximal caries with periapical abscess. No other pathology was detected [Figure 2]. Based on the clinical findings, a provisional diagnosis of TS was made. Other investigations such as thyroid function tests, echocardiography, liver function tests, and chromosomal analysis (GTG) G-Banding Using Trypsin and Giemsa banded karyotype were advised, and conventional chromosomal analysis from blood lymphocytes revealed a karyotype of 45X pattern [Figure 3]. Based on these investigations, the final diagnosis of TS was made and the patient was referred to the department of orthodontics for dental treatment and also she was referred to a pediatrician for further needful.
|Figure 1: Physical examination revealing short stature with a height of 114 cm and weight of 20 kg associated with microcephaly. (a) High-arched palate|
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|Figure 3: Conventional chromosomal analysis from blood lymphocytes revealing a karyotype of 45X pattern|
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| Discussion|| |
Despite being the most common chromosomal abnormality in females, only about 1% of embryos with this genetic defect survive to be born due to a high rate of fetal loss. Apart from obvious clinical stigmata, short stature, and hypogonadism, this condition is associated with dysfunctions and disorders of various systems. These include cardiovascular diseases (coarctation of aorta, aortic dissection, valvular heart diseases, and hypertension), skeletal deformities, hypothyroidism, osteoporosis, dyslipidemia, insulin resistance, renal disease, malignancies, dermatological diseases, and eating disorders. Though most patients with TS have normal intelligence, approximately 70% have deficits in specific areas of intellectual and cognitive abilities. In 1992, Held et al. sent an innovative idea about TS: Karyotype 45, X really does not exist, all Turner syndrome patients who survive and get to be born are really mosaic., The karyotype 45, X is really deleterious and the natural selection does not allow it, causing a spontaneous abortion in the 1st week of gestation. The presence of a second cellular line, either 46, XX or 46, XY, in embryonic or extra-embryonic tissues, provides a feto-protective effect which allows the development of a Turner syndrome girl.
Indications for karyotyping 
The indications for karyotyping are as follows:
- Unexplained growth failure
- Edema of hands and feet
- Left-sided cardiac anomalies
- Phenotypic somatic features
- Short stature
- Delayed puberty
- Chronic otitis media.
TS is the consequence of complete or partial absence of one X-chromosome in a female with short stature and gonadal dysgenesis. TS is a chronic disease associated with a wide range of malformations with varying frequencies in different populations mainly related to X-chromosomal rearrangements. Molecular studies have shown that the maternal X is retained in two-third of patients with TS and paternal X in the remaining one-third. More than one-half of all patients with TS have mosaic chromosomal complement. It was observed that the patients with 45X karyotype exhibit more severe phenotypes than those with mosaicism. TS is a chromosomal disorder and frequently is being misdiagnosed, therefore it is suggestive that any female with short stature and primary or secondary amenorrhea, with or without phenotypic features, should be confirmed by chromosomal analysis. Early recognition and timely investigation will improve their quality of life.
For the past several decades, a chromosomal karyotype has been the “gold standard” for the definitive diagnosis of TS, the diagnosis of TS requires not just the evidence of abnormal sex chromosomal complement, but also major clinical features, including short stature. Phenotypically normal adult women undergoing investigation of infertility may be found to have deletion of terminal portions of an Xq (long arm) without other features of TS and they should not be classified with TS. The phrase “complete or partial” is used to include several chromosomal etiologies leading to the syndrome. The most common is pure X monosomy (45, X – formerly designated 45 × 0).
In our case, conventional chromosomal analysis from blood lymphocytes revealed a karyotype of 45X pattern. No other abnormality was detected on oral examination other than high-arched palate. OPG showed no change in the bone density, and no other significant pathology was detected. Oral physicians and pediatric dentists need to be aware of major clinical features for definitive diagnosis of TS for early recognition and timely investigation which will improve their quality of life and will guide for the oral care.
| Conclusion|| |
The main clinical features of TS are short stature, gonadal dysgenesis, and congenital malformations. Moreover, most individuals with TS do not undergo pubertal development and exhibit primary amenorrhea due to accelerated loss of oocytes in the 45X, the variability that can occur in patients with TS and emphasizes the need to carefully assess unusual growth patterns in any child, regardless of other underlying conditions.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
The authors would like to thank Dr. Veena and Dr. Kavita, Department of Oral Medicine and Radiology, Coorg Institute of Dental Sciences, Virajpet, Coorg, Karnataka, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]