Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that almost exclusively affects girls
and is totally disabling. Three genes have been identified that cause RTT: MECP2, CDKL5 and FOXG1.
However, the etiology of some of RTT patients still remains unknown. Recently, next generation
sequencing (NGS) has promoted genetic diagnoses because of the quickness and affordability of the
method. To evaluate the usefulness of NGS in genetic diagnosis, we present the genetic study of RTT like patients using different techniques based on this technology. We studied 1577 patients with RTT like clinical diagnoses and reviewed patients who were previously studied and thought to have RTT
genes by Sanger sequencing. Genetically, 477 of 1577 patients with a RTT-like suspicion have been
diagnosed. Positive results were found in 30% by Sanger sequencing, 23% with a custom panel, 24%
with a commercial panel and 32% with whole exome sequencing. A genetic study using NGS allows the
study of a larger number of genes associated with RTT-like symptoms simultaneously, providing genetic
study of a wider group of patients as well as significantly reducing the response time and cost of the
study
