Rett syndrome: causes, symptoms and treatment

Rett syndrome is an autism spectrum disorder It begins in early childhood and occurs mainly in girls. It is characterized by the presence of microcephaly and the loss of motor skills acquired during the first months of life.

These and other symptoms are caused by genetic mutations related to the X chromosome. Although there is currently no cure for Rett's disorder, there are treatments and interventions that can alleviate the various problems it involves and improve the quality of life of girls with this syndrome.

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What is Rett syndrome?

In 1966 the Austrian neurologist Andreas Rett described a childhood-onset disorder consisting of “a cerebral atrophy with hyperammonemia ”, that is, characterized by excessive levels of ammonia in the blood. Later, the relationship of this syndrome with hyperammonemia would be refuted, but the clinical picture described by Rett would be baptized with his surname.

Rett syndrome is an alteration of physical, motor and psychological development

that occurs between the first and fourth year of life, after a period of normal growth. The most characteristic symptoms are the deceleration of cranial development and the loss of manual skills, as well as the appearance of stereotyped movements of the hands.

This disorder occurs almost exclusively in girls; in fact, both the ICD-10 and the DSM-IV state that it only affects women, but recently some cases of Rett syndrome have been detected in children.

Because men only have one X chromosome, in which the genetic defects typical of Rett syndrome are located, men symptoms are corrected to a lesser extent than in women, leading to more severe variants that carry a higher risk of death early.

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Relationship with other autism spectrum disorders

Currently the DSM-5 classifies it within the category “Autism Spectrum Disorders” (ASD), a label that it shares with other more or less similar syndromes that were differentiated in DSM-IV: the disorder Autism, Asperger's Syndrome, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder are not specified.

In this sense, Rett syndrome is considered a neurological disease, not a mental disorder. For its part, the ICD-10 classification categorizes Rett's disorder as an alteration of psychological development. Specifically, according to this medical manual it is a pervasive developmental disorder, a concept similar to that of DSM-IV.

Rett syndrome differs from childhood disintegrative disorder in that it usually begins earlier: while the former usually occurs before 2 years of age, childhood disintegrative disorder occurs slightly later and its symptoms are less specific. Furthermore, Rett syndrome is the only autism spectrum disorder that it is more prevalent in women than in men.

Symptoms and signs of this disorder

The prenatal and perinatal development of girls with Rett syndrome is normal for about the first 5 to 6 months of life. However, in some cases the little girl can continue to grow normally for up to 2 or 3 years.

After this period skull growth slows and motor skills decline, especially of the fine movements of the hands; consequently, repetitive or stereotyped manual movements develop, including twisting and wetting with saliva.

In addition to microcephaly and manual disturbances, people with Rett's disorder may have a number of associated signs and symptoms with a variable frequency:

• Severe intellectual disability.
• Gastrointestinal disorders such as constipation.
• Alterations in brain bioelectric activity and appearance of epileptic seizures.
• Absence of language or severe linguistic deficits.
• Deficits in social interaction, although interest in others is maintained.
• Walking difficulties, incoordination of gait and trunk movements.
• Inadequate chewing.
• Respiratory disorders such as hyperventilation, apnea or air retention.
• Scoliosis (abnormal curvature of the spine).
• Drooling
• Difficulties in toilet training.
• Brief spasms (chorea) and involuntary contortions (athetosis).
• Muscle hypotonia.
• Characteristic social smile during early childhood.
• Avoidance of eye contact.
• Screaming outbursts and uncontrollable crying.
• Bruxism (involuntarily clenching teeth).
• Cardiovascular disorders such as arrhythmia.

Causes

The cause of this disorder is the mutation in the MECP2 gene, which is located on the X chromosome and plays a fundamental role in the functioning of neurons. Specifically, MECP2 silences the expression of other genes, preventing them from synthesizing proteins when this is not necessary. It also regulates gene methylation, a process that modifies gene expression without altering DNA.

Although alterations in this gene have been clearly identified, the exact mechanism by which the symptoms of Rett syndrome develop is not known.

Mutations in the MECP2 gene in general do not depend on inheritance but are usually randomAlthough a family history of Rett's disorder has been found in a small number of cases.

Prognosis and treatment

Rett syndrome persists throughout life. Deficits are not usually corrected; rather, they tend to increase over time. In the event that it occurs, the recovery is discreet and is usually limited to the improvement of social interaction skills in late childhood or early adolescence.

The treatment of Rett syndrome is fundamentally symptomatic, that is, focused on reducing the multiple problems. Therefore, interventions vary depending on the specific symptom to be alleviated.

At the medical level, antipsychotic drugs and beta-blockers are usually prescribed, as well as selective serotonin reuptake inhibitors. Nutrition control can help prevent weight loss It typically stems from difficulties in chewing and swallowing food.

Physical, linguistic, behavioral, and occupational therapy can also be helpful in reducing the physical, psychological, and social symptoms of Rett syndrome. In all cases, intense and continuous support is required from different types of health services to empower girls with Rett to develop in the most effective way satisfactory possible.