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Comparative Study of Triple X Syndrome – A case report study

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Abstract:

Triple X syndrome is one of the most common genetic disorders which affect the female population with a frequency of 1 in 1000 live births. Due to its less distinct characteristics and variation in the patterns, the patient remains undiagnosed. This disorder has larger socio-psychological implications on the patient’s health. A case study of the triple X syndrome (47, XXX) is compared with two other case studies of other patterns that have already been published. Infertility and amenorrhea are found to be the presenting features of this syndrome. Cytogenetic analysis (karyotyping) revealed confirmation of Triple X syndrome by the presence of extra X chromosome. This study is contemplated to explore the different patterns of Triple X syndrome drawn from a comparative study in order to enhance a better and a deeper understanding of the disorder. Keywords: Triple X syndrome, infertility, amenorrhea.

Introduction:

Triple X Syndrome is one of the most common genetic syndromes by which females are affected with a frequency of 1 in 1000 live female births. This syndrome is characterized by an extra X chromosome and hence represented as 47, XXX. The disorder is said to occur because of a random error during meiotic division in the gametes of either the mother or the father. In some cases, the error occurs during the development of the embryo and this results in mosaic pattern of Triple X syndrome, where only a few cells have an extra X chromosome. The following case study is of the Triple X syndrome (47, XXX) showing no unusual physical symptoms and comparison of the above case with already published case studies of Triple X Syndrome (47,XXX) and mosaic Triple X syndrome (45,XO/47,XXX).

Case Report:

A 22 year old female visited Out Patient Department of Regional Research Institute of Unani Medicine (Government of Unani Hospital, Chennai) with complaints of absence of normal menstrual flow and failure to conceive with itching and skin lesions over the extremities. Her height was 5’1” and she weighed 44kg at the time of her visit. She was conceived when her mother was 36 years old. She has 3 older sisters who have all been able to conceive without any difficulty. No history of consanguineous marriages or genetic abnormalities in family. Menarche was at 12 years. Her academic record and Intelligence quotient (IQ) was of average value and had completed her education up till 12th grade. She was married at 19 years to a 28 year old male.

Endocrinology tests revealed her Luteinizing hormone (LH) levels to be 9.78 mIU/mL and Follicle Stimulating Hormone (FSH) levels to be 16.01 mIU/mL. Her Estradiol level was 22.10 pg/mL.

Transvaginal sonography of pelvis showed a retroverted uterus measuring 4 cm. Fundal end of the cavity contained echogenic lesion measuring 1.2 ? 0.8 cm. right ovary appeared smaller than normal measuring 2.2 ? 1.0 cm and no follicular activity was seen. Left ovary measured 2.2 ? 1.0 cm, containing one follicle. Anti-mullerian hormone (AMH) levels were below 0.1 ng/mL (normal= 0.9-9.5 ng/mL)

Karyotyping by G-banding Peripheral Blood was done. 20 cells were counted and analyzed and all the cells counted showed the presence of an extra X chromosome.

Discussion:

In the case of patients with Triple X syndrome (47, XXX) there are distinct symptoms. Toddlers show delayed language development. They show accelerated growth until puberty. Electroencephalogram (EEG) abnormalities seem to be rather common. Many girls show motor-coordination problems and auditory processing disorders are not rare. Verbal IQ is the lowest[1]. Oral abnormalities such as midfacial hypoplasia (the upper jaw, cheekbones and eye sockets do not grow as much as the rest of the face), delayed eruption, congenital absence of teeth, and taurodontism (the body of the tooth and pulp chamber is enlarged vertically at the expense of the roots) have also been found in this syndrome [2,3]. It seems that most women with Triple X syndrome have no problem in becoming pregnant and can expect to have healthy children, although a high prevalence of cardiac and neural defect and sex chromosomal abnormalities have been reported in infants [4]. As seen in the above case study the physical signs and symptoms associated with the syndrome is almost none and is the chief reason why affected women go unnoticed. The following pedigree of the patient shows that this syndrome is not inherited and occurs due to a random error.

Affected females are more likely to be diagnosed in childhood for short stature, or later for primary or secondary amenorrhea or during evaluation for pregnancy. The only proven mean of achieving pregnancy in infertile women with Triple X is Assistive Reproductive Technology (ART) with donor oocyte. Premature ovarian failure can be treated with Hormone Replacement Therapy [5]. But other parameters such as the hormone levels, ovarian function of the patient should be observed before proceeding to ART.

Mitchell J. Machiela et al investigated the frequency of large-scale chromosome X mosaicism (>2 Mb) in blood or buccal samples from 38,303 women. They observed an overall frequency of X mosaicism of ?0.25%, roughly four times the mean autosomal rate. The frequency of X mosaicism increases with increasing age, but is not associated with non-haematologic cancer risk.[6]

Majority of the affected females with mosaic pattern (46, XX/ 47, XXX) show no physical symptoms and might have a higher risk of infertility. In a few cases, patients who could not conceive naturally have been able to, through Invitro Fertilization (IVF) technique.

A. Venkateshwari et al reported a case of mosaic triple X and mosaic Turner’s syndrome. In a cytogenetic study 50 metaphase plates were analyzed which revealed mosaicism of 45,XO/ 47,XXX chromosomal constitution . Turner mosaics usually have a less severe phenotype and up to 40% enter puberty spontaneously before culminating into gonadal failure[7]. Normal height, micrognathia, a downward droop of the outer corner of the eyes and epicanthic folds[8] are a few symptoms that are observed.

Physical symptoms

Increased height and weight, delayed speech, epicanthal folds, hypertelorism

Average height and weight, amenorrhea, infertility

Normal height, drooping eyelids, dry eyes, Presence of Cubitus valgus , absence of Axillary & pubic hair

Genetic abnormalities in family None None None

IQ Level Low to average Average Average

FSH value Normal to high Normal Post menopausal range

LH value Normal Normal Post menopausal range

USG Findings:

Uterus

Slightly smaller

Retroverted and smaller

Small

Ovaries Hypoplastic Hypoplastic

Absent

Fertility Very rarely infertile

Abnormality not passed Infertile Mostly impaired fertility

Conclusion:

The degree to which the characteristics are expressed may vary from one patient to another. This syndrome which results due to a random error is thought to occur in children of women conceiving above the age of 35. Hence delayed marriages and deferred conceiving is to be avoided. Chromosomal karyotype test is mandatory for diagnosis. Depending on how early the syndrome is diagnosed, speech therapy and counseling can be provided.

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