The most likely diagnosis is a case of the intractable convulsions mental defect and facial nevus is-
Sturge Weber syndrome and Von-Reckling-Hausen disease (NF-1) have been explained earlier about other options. 

Tuberous sclerosis ( Bourneville's disease)

Tuberous sclerosis is characterized by : -


Cutaneous lesions → Adenoma sebaceum, ash-leaf shaped hypopigmented macules, shagreen patches, depigmented nevi.
Seizures
Mental retardation


Other features  → Calcified subependymal nodules, Subependymal giant cell astrocytoma, ependymoma,

Rhabdomyomas of the heart, and angiomyomas of the kidney, liver, adrenals and pancreas.
Von Hippel - Lindau syndrome

This syndrome consists of Retinal, cerebellar and spinal hemangioblastoma.
Renal cell carcinoma, Pheochromocytoma, benign cyst of the kidney, liver, pancreas and epididymis may also occur.
Polycythemia may occur due to secretion of erythropoietin from hemangioblastoma.
Sturge Weber syndrome
Tuberous sclerosis
Von-Hippen -Lindau disease
Von- Reckling-Hausens disease