Association of Down syndrome and tuberous sclerosis and their similarities in m-TOR pathway overactivation. About a case

Background

The association between Down syndrome and Tuberous sclerosis (DS/TSC) has very rarely been described. These two entities present in common overactivation of the m-TOR system (mammalian rapamycin ligand), which has been related to abnormal neuronal growth, abnormal synaptic transduction and neurotransmitter overstimulation in different brain areas (among others) that result in cognitive retardation and autistic symptoms.

Case summary

We present a girl with a diagnosis of DS, with early childhood onset presenting convulsive tonic-clonic seizures and hypopigmented skin plaques. A brain MRI revealed cortical tubers suggestive of TSC. A subsequent echocardiogram showed the presence of multiple endomyocardial lesions suggestive of rhabdomyoma. Further follow-ups showed spontaneous resolution of these cardiac lesions, but persistence of brain disorders. We also describe the refractoriness of the convulsive events despite appropriate treatment with multiple anticonvulsants.

Conclusions

Neurological and cardiac implications in patients with DS/TSC association lead to a difficult therapeutic scenario with a high rate of complications, partially due to symptomatic refractoriness. New drugs aimed at the m-TOR signalling pathway could be very useful in this picture, given its relationship to improvement of cognitive impairment and tumours associated with these two entities.