Treatment contingent upon etiology: Two adult female patients with mild intellectual disability and a causative copy number variation

Objective: While modern genetic techniques have substantially increased the knowledge regarding causes of intellectual disabilities and related neuropsychiatric disorders, a marked time-lag can be noticed with respect to its implementation in common psychiatric practice. Given the relatively strong emphasis on diagnostic classification to the disadvantage of phenomenological and etiopathophysiological factors, the application of etiology-based treatment strategies may be seriously hindered. This a fortiori holds for patients with mild intellectual disability in the absence of salient dysmorphic features or congenital anomalies.
Method: The present paper illustrates this by means of two adult female patients with mild intellectual disability and late onset of symptoms from the mood and cognitive spectra.
Results and conclusions: In both patients microarray analysis disclosed de novo copy number variations, being a 2.05 Mb mosaic interstitial deletion in 7p21.1p15.3 in patient A and a 1.48 Mb interstitial duplication in 17q12 in patient B. These findings led to an appropriate diagnosis and gave direction to a significant change in treatment that resulted in an improvement of general functioning.