He Patau's syndrome Is a congenital disease of genetic origin, due to the presence of a trisomy on chromosome 13 (Ribate Molina, Uriel and Ramos sources, 2010).
Specifically, Patau syndrome is the third most common autosomal trisomy after Down syndrome and Edwards syndrome (Fogu et al. 2008).
At the clinical level, this pathology affects multiple systems. In this way, there are several alterations and abnormalities in the nervous system, delay Generalized growth, cardiac, renal and musculo-skeletal malformations (Ribate Molina, Uriel and Ramos sources, 2010).
Diagnosis is usually performed during gestation in most cases, as clinical findings can be detected on ultrasound (Ramos Fuentes, 2016).
However, to rule out false positives and misdiagnoses, a number of genetic tests are often performed to identify trisomy 13 (Ribate Molina, Uriel and Ramos sources, 2010).
As for treatment, there is currently no cure for Patau syndrome, the survival of those affected does not usually exceed the year of life. The The most common causes of death are cardiorespiratory complications (Ramos Fuentes, 2016).
Characteristics of Patau's syndrome
Patau syndrome, also known as trisomy 13, is a medical pathology of genetic origin that is associated with severe intellectual disability As well as multiple physical disorders (Genetics Home Reference, 2016).
The affected persons usually present serious cardiac anomalies, diverse alterations in the nervous system, musculoskeletal malformations, Facial alterations, muscle hypotonia, among others (Genetics Home Reference, 2016).
Due mainly to the severe multisystemic involvement, people affected by Patau's syndrome usually have a very long life expectancy. Reduced (Best, 2015).
This syndrome was initially identified in 1960 as a cytogenetic syndrome, ie, a genetic disorder associated with an abnormality Chromosome (Best, 2015).
Chromosomes make up the genetic material of the cells that make up our body. Specifically, the chromosomes are constituted by the acid Deoxyribonucleic acid, also known by its acronyms DNA, in addition also presents a composition characterized by the presence of different substances Proteins.
These chromosomes are usually organized structurally in pairs. In the case of humans, we present 23 pairs of chromosomes, taking in total 46 of these.
In the case of Patau syndrome, the genetic abnormality specifically affects chromosome 13. The affected individuals have trisomy of the Chromosome 13, that is, they have three copies thereof.
At a more specific level, each ovum and each sperm contain 23 Chromosomes Each, with the genetic material of the maternal and paternal parent (Stanford Children's Health, 2016).
At the time of fertilization, the union of both cells results in the creation of 23 chromosome pairs, or the presence of 46 chromosomes in total (Stanford Children's Health, 2016).
However, there are occasions in which an error or an event altered during the union, results in the presence of genetic abnormalities, such as presence Of an extra chromosome in one of the couples (Stanford Children's Health, 2016).
In this way, this altered process will provoke a succession of neurobiological events during fetal development, which will alter gene expression Normal or expected, giving rise to the presence of an organic affectation in diverse systems.
About us
Patau syndrome or trisomy 13 is considered a rare or rare disease. Different investigations, consider that this pathology presents An approximate frequency of 1 case per 5,000-12,000 newborns (National Organization for Rare Disorders, 2007).
Despite this, in many cases the gestation of those affected by Patau syndrome does not usually come to term, so the frequency Can be significantly increased (National Organization for Rare Disorders, 2007).
Thus, it has been observed that the annual rate of spontaneous abortion in this pathology is high, represented approximately 1% of the total of these (Ramos Sources, 2016).
As to the distribution of Patau syndrome by sex, it has been observed that this pathology affects women more frequently than men (Genetics Home Reference, 2016).
Characteristic signs and symptoms
At the clinical level, Patau syndrome can affect very heterogeneously in the body and between different cases, making it difficult to establish Which are the cardinal signs and symptoms of this pathology.
However, different clinical reports such as that of Ribate molina, Puisac Uriel and Ramos Fuentes (2010), highlight which are the most clinical findings Frequent in those affected by Patau syndrome or trisomy 13:
Alteration of growth
The presence of generalized growth retardation is one of the most frequent clinical findings. Specifically, growth may be observed Slow or delayed in the prenatal and postnatal stages in approximately 87% of cases of Patau's syndrome.
Alterations and malformations in the central nervous system (CNS)
In the case of the nervous system, there are several clinical findings that may be observed: hypotonia / hypertonia, apnea crisis, holoprosencephaly, Microcephaly , Psychomotor retardation or severe intellectual disability.
- Hypotonia / Muscle hypertonia : the term Hypotonia Refers to the presence of muscle flaccidity or reduced muscle tone, due to its In part, the term hypertonia refers to the presence of an abnormally high muscle tone. Both medical events occur in 26-48% of Affected individuals.
- Crisis or episodes of apnea : Apnea episodes are usually present in approximately 48% of cases and consists of one Reducing or stopping the breathing process for a short period of time.
- Holoprosencephaly that term Refers to the presence of different malformations at the brain level, Majority to the earlier portion. This clinical finding can be observed in approximately 70% of Patau's syndrome cases.
- Microcephaly : About 86% of those affected have a lower than expected cranial perimeter for their sex and level Maturational.
- Psychomotor retardation : As a consequence of the various physical malformations, individuals suffering from Patau syndrome will Present serious difficulties in coordinating and carrying out all kinds of motor acts. This finding can be observed in 100% of the cases.
- Severe intellectual disability : Cognitive impairment and severe intellectual disability is a clinical finding presented in the Of all diagnosed cases of Patau's syndrome. Both neurological conditions develop as a result of nervous system.
Craniofacial abnormalities and malformations
At the facial and cranial level, there are also several clinical signs and symptoms that can be observed:
- Flattened front : Abnormal development of the frontal part of the skull is a sign present in all cases of syndrome Patau.
- Eye disorders : In the case of anomalies and pathologies that affect the eyes, they are present in approximately 88% Of cases, the most frequent being microphthalmina, iris coloboma or ocular hypotelorism.
- Diverse malformations in the auricle : Progression of facial and cranial anomalies may also affect the flag At 80% of cases.
- Cleft lip and cleft palate : Both oral malformations are present in approximately 56% of affected individuals. He Term refers to the presence of an incomplete closure of the lips, showing a fissure through the medial area, whereas the term Cleft palate refers to an incomplete closure of the entire structure that forms the roof of the mouth .
Musculoskeletal malformations
Musculoskeletal anomalies and malformations can affect various areas, the most common being the neck and extremities.
- Neck : The anomalies that affect this particular area are present in many cases, in particular can be observed a Short or poorly developed neck in 79% of those affected, while an excess of skin in the nape of the neck is present in 59% of cases.
- Extremities : Alterations affecting the extremities are diverse, it is possible to observe polidactyly in 76% of those affected, Fingers flexed or overlapped in 68%, grooves in the hands in 64%, or hyperconvex nails in 68% of those affected.
Cardiovascular System Disorders
Anomalies related to cardiovascular system , Are the most serious medical condition in Patau syndrome, as it seriously threatens the Survival of those affected.
In this case, the most frequent findings are intraventricular communication in 91%, persistence of ductus arteriosus in 82%, and Ventricular septal defect in 73%
Disorders of the genitourinary system
The manifestations of the genitourinary system are usually related to the presence of cryptorchidism in males, polycystic kidney, uterus Bicorne in females and hydronephrosis.
Causes
As we pointed out earlier, Patau syndrome is associated with the presence of genetic abnormalities on chromosome 13.
Most of the cases are due to the presence of three complete copies of the Chromosome 13 , So the extra genetic material alters the development Norm, and thus giving rise to the clinical course characteristic of Patau syndrome (Genetics Home Reference, 2016).
However, there are also cases of Patau syndrome due to duplications of parts of chromosome 13. It is possible that some people affected Present all intact copies of it and one extra attached to another chromosome (Genetics Home Reference, 2016).
In addition, cases have also been reported in which individuals only present this type of genetic alteration in some cells of the body. In this In this case, the pathology acquires the name of trisomy 13 in mosaic, and therefore the presentation of signs and symptoms will depend on the type and number of Affected cells (Genetics Home Reference, 2016).
Diagnosis
People affected with Patau syndrome present a set of clinical manifestations that are present from the moment of birth.
Based on observation of the signs and symptoms, it is possible to make a clinical diagnosis. However, when suspicion exists, it is imperative To perform other complementary tests to confirm the presence of Patau's syndrome.
In these cases, the tests of choice are the genetic tests of the Karyotype , They are able to give us information about the presence / absence of An extra copy of chromosome 13.
In other cases, it is also possible to perform the diagnosis in the prenatal stage, the routine ultrasound can show indicators of Alarm, so, in general, genetic analyzes are requested to confirm their presence.
The most common tests in the prenatal stage are fetal ultrasound, amniocentesis And sampling of chorionic villi (National Organization for Rare Disorders, 2007).
In addition, once the definitive diagnosis of Patau's syndrome has been made, either in the prenatal or postnatal phase, it is Continuous medical follow-up to detect at an early stage possible medical complications that endanger the survival of the person (National Organization for Rare Disorders, 2007).
Treatment
At present, there is no specific or curative treatment for Patau syndrome, therefore, therapeutic interventions will be oriented Towards the treatment of medical complications.
Due to the severe multisystemic involvement, people affected by Patau syndrome will require medical assistance from the time of Birth (Ramos Fuentes, 2016.
On the other hand, the cardiac and respiratory alterations are the main causes of death, therefore, it is essential to perform a Follow-up and detailed medical treatment of both conditions (Ramos Fuentes, 2016).
In addition to pharmacological intervention for different signs and symptoms, it is also possible to use surgical procedures for the correction of Some malformations and musculoskeletal abnormalities.
In summary, the treatment of Patau syndrome or trisomy 13 will be specific depending on each case and the associated clinical course. Generally, the Intervention usually requires the coordinated work of different specialists: pediatricians, cardiologists, neurologists, etc. (National Organization for Rare Disorders, 2007).
References
- Best, R. (2015). Patau Syndrome . Obtained from Medscape.
- Genetics Home Reference. (2016). Trisomy 13 . Retrieved from the Genetics Home Reference.
- NIH. (2016). Trisomy 13 . Obtained from MedlinePlus.
- NORD. (2007). Trisomy 13 . Retrieved from the National Organization for Rare Disorders.
- Orphanet. (2008). Trisomy 13 . Obtained from Orphanet.
- Ramos Fuentes, F. (2016). Patau's syndrome (Trisomy 13). Obtained from Trisomy 18.
- Ribate Molina, M., Puisac Uriel, B., & Ramos Fuentes, F. (2010). Trisomy 13 (Patau Syndrome). Spanish Association of Pediatrics , 91-95.
- Stanford Children's Health. (2016). Trisomy 18 and 13 . Retrieved from Stanford Children's Health.