Electroclinical phenotype in Rubinstein-Taybi syndrome

Objective: Rubinstein-Taybi syndrome (RSTS) is a rare congenital disorder (1:125.000) characterized by growth retardation, psychomotor developmental delay, microcephaly and dysmorphic features. In 25% of patients seizures have been described, and in about 66% a wide range of EEG abnormalities, but studies on neurological features are scant and dated. The aim of this study is to describe the electroclinical phenotype of twenty-three patients with RSTS, and to try to correlate electroclinical features with neuroradiological, cognitive and genetic features.

Patients and methods: Electroclinical features of twenty-three patients with RSTS (age between18months and 20years) were analyzed. Sleep and awake EEG was performed in twenty-one patients, and brain MRI in nineteen patients. All subjects received cognitive evaluation.

Results: EEG abnormalities were observed in 76% (16/21) of patients. A peculiar pattern prevalent in sleep, characterized by slow monomorphic activity on posterior regions was also observed in 33% (7/21) of patients. Almost no patient presented seizures. Eighty-four percentage of patients had brain MRI abnormalities, involving corpus callosum and/or posterior periventricular white matter. Average General Quotient (GQ) was 52, while average IQ was 55, corresponding to mild Intellectual Disability. The homogeneous electroclinical pattern was observed mainly in patients with more severe neuroradiologic findings and moderate Intellectual Disability/Developmental Disability (ID/DD). No genotype-phenotype correlations were found.

Conclusion: The specific electroclinical and neuroradiological features described may be part of a characteristic RSTS phenotype. Wider and longitudinal studies are needed to verify its significance and impact on diagnosis, prognosis and clinical management of RSTS patients.