Highlights► Our study provides new insights into the pre-regressional development of RTT. ► The pre-regression period should not be considered asymptomatic. ► Peculiarities in speech-language development are potential red flags for RTT.

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ABBREVIATIONSPSV Preserved speech variant RTT Rett syndrome AIM Our aim was to contribute new findings related to the pre-regressional verbal development of females with a variant of Rett syndrome (RTT) as the loss of spoken language is one of the key clinical features of RTT, and it would be of particular interest to study the early speech-language development of females who are considered to have preserved some speech-language abilities.METHOD We analysed 461 minutes of audio-video recordings containing play situations and the daily routines of six females (aged 7 to 24 months; mean birthweight 3057g, SD 195g) with the preserved speech variant (PSV) of RTT. All videos were recorded by parents and analysed retrospectively after the diagnosis PSV was made.RESULTS From the age of 7 months onwards, we observed two types of vocalizations, appearing intermittently: (1) apparently normal sequences; and (2) atypical (i.e. inhalatory, pressed, or high-pitched crying-like) vocalizations. Some participants failed to reach the milestone of canonical babbling. We observed a limited phonological and lexical complexity and a restricted compositional variability. Volubility was reduced during the whole period under observation. Hand stereotypies with simultaneous atypical vocalizations appeared only during the second year of life. INTERPRETATIONThe intermittent character of normal versus abnormal verbal behaviours might contribute to an early identification of children with a possible genetic mutation, and provides evidence that speech-language functions are abnormal from the very beginning.Rett syndrome (RTT, MIM 312750), a profoundly disabling neurodevelopmental disorder that predominantly occurs in females, is mainly caused by mutations in the gene MECP2 for the methyl-CpG-binding protein 2 (Xq28).1 It is assumed that MeCP2, a regulator of neuronal activity-dependent synaptic maturation, plays a central role in postnatal brain development. Disruption of MeCP2 affects a wide range of neurodevelopmental functions such as cognitive processes, purposeful hand use, and communicative abilities.2 The pathogenesis of RTT is characterized by a four-stage trajectory, the second of which is the regression period, in which the clinical signs become more prominent.1 The trajectory can be observed in females with classic RTT as well as in other variants of RTT, of which the so-called preserved speech variant (PSV) or Zappella variant (Z-RTT) has a more benign overall pathogenesis, including better manual and speech-language abilities. 1,3,4 Females with PSV have the same staging and a number of the same symptoms as in classic RTT (e.g. the characteristic hand stereotypies) but usually show no general growth failure or deceleration of head growth; epilepsy and hyperventilation are rare.3-5 Furthermore, individuals with PSV show a postregressional improvement in hand use; language abilities may be regained or preserved. Lexicon size and syntactic complexity are reported to increase slowly, but are usually accompanied by features such as e...

Rett syndrome (RTT) is a devastating neurodevelopmental disorder that affects one in ten thousand girls and has no cure. The majority of RTT patients display mutations in the gene that codes for the methyl-CpG-binding protein 2 (MeCP2). Clinical observations and neurobiological analysis of mouse models suggest that defects in the expression of MeCP2 protein compromise the development of the central nervous system, especially synaptic and circuit maturation. Thus, agents that promote brain development and synaptic function, such as insulin-like growth factor 1 (IGF1), are good candidates for ameliorating the symptoms of RTT. IGF1 and its active peptide, (1–3) IGF1, cross the blood brain barrier, and (1–3) IGF1 ameliorates the symptoms of RTT in a mouse model of the disease; therefore they are ideal treatments for neurodevelopmental disorders, including RTT. We performed a pilot study to establish whether there are major risks associated with IGF1 administration in RTT patients. Six young girls with classic RTT received IGF1 subcutaneous injections twice a day for six months, and they were regularly monitored by their primary care physicians and by the unit for RTT in Versilia Hospital (Italy). This study shows that there are no risks associated with IGF1 administration.

SUMMARYObjective: Rett syndrome is an X-linked dominant neurodevelopmental disorder caused by mutations in the MECP2 gene, and characterized by cognitive and communicative regression, loss of hand use, and midline hand stereotypies. Epilepsy is a core symptom, but literature is controversial regarding genotype-phenotype correlation. Analysis of data from a large cohort should overcome this shortcoming. Methods: Data from the Rett Syndrome Networked Database on 1,248 female patients were included. Data on phenotypic and genotypic parameters, age of onset, severity of epilepsy, and type of seizures were collected. Statistical analysis was done using the IBM SPSS Version 21 software, logistic regression, and Kaplan-Meier survival curves. Results: Epilepsy was present in 68.1% of the patients, with uncontrolled seizures in 32.6% of the patients with epilepsy. Mean age of onset of epilepsy was 4.68 AE (standard deviation) 3.5 years. Younger age of onset was correlated to severity of epilepsy (Spearman correlation r = 0.668, p < 0.01). Patients with late truncating deletions had lower prevalence of epilepsy. Compared to them, the p.R133C mutation, associated with a milder Rett phenotype, increased the risk for epilepsy (odds ratio [OR] 2.46, confidence interval [CI] 95% 1.3-4.66), but not for severe epilepsy. The p.R255X mutation conferred an increased risk for epilepsy (OR 2.07, CI 95% 1.2-3.59) as well as for severe epilepsy (OR 3.4, CI 95% 1.6-7.3). The p.T158M and p.C306C mutations relatively increased the risk for severe epilepsy (OR 3.09 and 2.69, CI 95% 1.48-6.4 and 1.19-6.05, respectively), but not for epilepsy occurrence.