Genetic Mutations: Turner syndrome

Turner syndrome

DEFINITION

Turner syndrome (TS) is a disorder chromosomal characterized by: short stature, gonadal dysgenesis with infantilism sexual, webbed neck, low ulnar angle, low implantation partial or total hair and monosomy chromosome X.

The birth prevalence is 1/2000 1/5000 live NB women. About 1% of all conceptions have a monosomy X. Of these most end in spontaneous abortions, usually during the first trimester of pregnancy.

 

karyotype síndrome

Clinical features

Musculoskeletal                                  Frequency (%)

Short stature . . . . . . . . . . . . . . . . . ………..100

Sort neck . . . . . . . . . . . . . . . . . . . ……….40

Abnormal ratio upper / lower segment. . . . . .97

Cubitus valgus . . . . . . . . . . . . . . . . . ………47

Short metacarpals. ... . ... . . . . . . . . ………37

Madelung deformity . . . . . . . . . . . . . ……..8

Scoliosis. . . . . . . . . . . . . . . . . . . . . .  ……..35

Genu valgus . . . . . . . . . . . . . . . . . ..............35

Micrognathia and high-arched palate. . . . . . . . . 38

And widely spaced hypoplastic nipples. . . . . . . . . 80

Lymphatic obstruction

Webbed neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Low-set hair . . . . . . . . . . . . . . . . . . . . . . . . . . . . …42

Edema of hands and feet . . . . . .  . . . . . . . . . . . . . 80

Dysplasia of the nails. . . . . . . . . . . . . . . . . . . . . . . 13

Dermatoglyphics characteristic. . . .  . . . . . . . . . . . 35

Germ cell defects

Gonadal failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Infertility . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 99

Other anomalies

Cardiovascular . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Kidney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Pigmented nevi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Ptosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Strabismus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Hearing impairment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

Associated anomalies

Hashimoto's thyroiditis . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 4

Hypothyroidism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10

Alopecia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Vitiligo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Gastrointestinal abnormalities . . . . . . . . . . . . . . . . . . . . . 3

Carbohydrate intolerance. . . . . . . . . . . . . . . . . . . . . . . . . 40

Diagnosis

The most important diagnostic test to be performed in suspected a case of Turner syndrome is the karyotype, which is defined as the pattern of the chromosomes of a species. For this test a blood sample taken from the patient and grown in the laboratory. About 50% of patients with Turner syndrome have the pattern 45, XO is, they lack a chromosome X. Then, the results are frequently partial loss of pieces of chromosomes (deletions), or arm full X chromosome or mixture of several of them in different cells (what is known as tiles).

Prenatal diagnosis 

It takes place before birth by analyzing fetal cells, which can be achieved by carrying out various tests:

·               Chorionic villus sampling: This technique, fetal cells, chorionic villi from the placenta originate that are obtained by cell culture. It takes place between the ninth and the twelfth week of pregnancy.

·               It can perform amniocentesis, which consists of a puncture through the wall of the uterus to withdraw fluid (in the floating fetal cells) - between weeks 14 and 16 of pregnancy.

·               And finally, with the funiculocentesis or direct puncture of umbilical cord blood for the fetus. It can be performed after the twentieth week of pregnancy.

Through an ultrasound study you may suspect that the fetus is affected by Turner Syndrome; the most common abnormalities are cystic hygroma (lymph fluid filled cavity) in the neck of the fetus, present in 88% of cases; hydrops (abnormal accumulation of fluid), 80%; short femur, in 59% of patients; malformations of the heart, in 48%; and brachycephaly (flattening of the skull bones), 32% of those affected.

Treatment

Treatment of patients with ST It requires regular monitoring and assessment at different ages. We must always consider the following points: 

• Examination of peripheral pulses and TA-making. We must not forget that hypertension occurs in the ST and they should be discarded or cardiac causes kidney.
• Evaluate each visit the possibility of serous otitis media and otitis are causes
• Frequently hearing loss.
• Gonadal hormone treatment failure, ie estrogen therapy Development of characters secondary sex.
• Treatment of short stature hormone growth (GH).
• To consider performing plastic surgery neck if the patient shows signs dysmorphic marked
• Monitoring diet and weight control to avoid obesity.
• Annual monitoring of glucose in urine to rule IGT and / or diabetes mellitus.
• Psychological support
• Encourage collaboration with associations corresponding sick.
• As discussed above, when there are a variety of mosaicism and in some cell lines
• There is the Y chromosome, you must dysgenic remove the gland, risk of malignancy (risk of gonadoblastoma)
  
  Bibliography:
  AURORA APARICIO MANRIQUE. (S/f). Mutations. 05/10/15, de biology 2 website: http://ies.rosachacel.colmenarviejo.educa.madrid.org/aurora.pdf
  Jose s. ramil. (S/f). Mutations. 12/10/15, de ciencias Sitio web: http://www.tirsoferrol.org/ciencias/pdf/a10_mutacion.pdf
  Paola Cerruti Mainardi. (2006). Orphanet Journal of Rare Diseases. BioMed Central, 33, 1-9.
  Enrique Gómez Galán. (S / F). Turner syndrome. 23.10.15, Spanish Association of Pediatrics Website: http://www.spao.es/documentos/biblioteca/entrada-biblioteca-fichero-60.pdf
  Health Secretary. (2007). National Center for Gender Equity and Reproductive Health. 30 / October / 2015, of Children's Rehabilitation Center Telethon, the Group of Birth Studies AC, John Langdon down Foundation, AC Website: http://www.salud.gob.mx/unidades/cdi/documentos/Sindrome_Down_lin_2007.pd