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Rett's Disorder Causes

(Also Known As: Retts Disorder Causes, Rett's Causes, Retts Causes, Autism Causes, Pervasive Development Disorder Causes, Mental Retardation Causes, Neurological Disorder Causes)

(Reviewed by: Paul Peterson, Licensed Therapist)

What causes Rett’s Disorder?

The etiology behind Rett’s disorder was discovered in 1999. A genetic mutation on the long arm of the X chromosome (Xq28) at a locus known as MECP2 claimed to have been the root of the condition. The gene produces a protein known as MeCP2, which is a vital factor for the normal development of the human brain. Due to this mutation, other genes remain active at stages in the brain development when they are not needed, thus interfering with the normal pattern of development and maturation of the brain's functions. Previously, Rett’s disorder was thought to result from degeneration or deterioration of brain tissues, but the discovery of the Rett's gene provides evidence that the disorder may be due to a failure of normal brain development. Particular regions of the brain in Rett's patients essentially remain at an infantile stage of development. According to geneticists, RS is an X-linked dominant disorder with a high rate of new mutations. 99.5% of these mutations occur during fetal development, while only 0.5% of cases are recurrences within families. Because RS is the first disorder in humans to be traced from defects in a protein that controls the expression of other genes through its interaction with methylated DNA, the Rett gene discovery paved the way to a new class of genetic diseases that might extend far beyond RS in its applications to other disorders related to developmental failures of the nervous system. 4

Mutations in the gene MECP2 located on the X chromosome can arise sporadically or from germline mutations.

  • Sporadic mutations - 95% or more of RS is usually caused by an uninherited mutation in the child since parents are generally genotypically normal or without MECP2 mutation. In sporadic cases of Rett syndrome, it is thought that the mutated MECP2 is derived from the male copy of the X chromosome. However, the cause of the sperm mutation is unknown and such mutations are rare.
  • Germline mutations - MECP2 is found near the end of the long arm of the X chromosome at Xq28. Phenotypically normal mothers who have a germline mutation in the gene encoding methyl-CpG-binding protein-2, MECP2 are able to pass these genetic defects to their offspring. An atypical form of Rett syndrome, characterized by infantile spasms or early onset epilepsy, can also be caused by a mutation to the gene encoding cyclin-dependent kinase-like 5 (CDKL5). Rett syndrome affects one in every 12,500 female live births by age 12 years. 5

Could You Have Rett's Disorder?

Rett's Disorder Topics

Related Conditions

Asperger's Syndrome – autism, delayed development in motor, communication and social skills, cognitive impairment, clumsiness
Autism – brain development disorder, Asperger’s disorder, impaired social interaction, restricted and repetitive behavior
Childhood Disintegrative Disorder - late onset of delayed development, impaired social, motor and communication skills
Pervasive Developmental Disorder NOS - delayed development in social, communication and motor skills