Hypochondroplasia (HCH) and Muenke syndrome (MS) are caused by mutations on 
FGFR3 gene. FGFR3 is known to play a role in controlling nervous system 
development. We describe the clinical and neuroradiological findings of the 
first two patients, to our knowledge, affected by HCH and MS, respectively, in 
whom bilateral dysgenesis of the medial temporal lobe structures has been 
observed. In both patients diagnosis was confirmed by molecular analysis. They 
were mentally normal and showed similarities in early-onset temporal 
lobe-related seizures. In both patients EEG recorded bilateral temporal region 
discharges. MRI detected temporal lobe anomalies with inadequate differentiation 
between white and gray matter, defective gyri, and abnormally shaped 
hippocampus.