Neurodevelopmental disorders caused by rare gene mutations are commonly referred to as Rare Genetic Neurodevelopmental Syndromes (RGNS). Witteveen-Kolk syndrome (WITKOS) is such an RGNS, caused by heterozygous variations in SIN3A and characterized by developmental problems, facial dysmorphisms, short stature, brain abnormalities, intellectual disability and behavioral problems. Although developmental and behavioral problems are expected to have a negative effect on the quality of life of patients and their caregivers, care for individuals with WITKOS mainly focuses on somatic characteristics. To address this issue, our (ProMiSe) project aims to first identify the behavioral and neurocognitive profile of patients with WITKOS (as well as patients with KBG-, Coffin-Siris- and FOXP1- Syndrome) and to develop and evaluate treatment of behavioral and neurocognitive problems for these patients.

Illustrating this approach, we present a case-study of the first documented treatment of behavioral problems in a 27-year-old single female with WITKOS. She had developmental problems during childhood, a history of severe psychiatric problems and received the genetically confirmed diagnosis of WITKOS at the age of 25. Extensive assessment of intellectual and neuropsychological functioning enabled personalized treatment strategies based on her behavioral- and neurocognitive functioning. The treatment program consisted of 12 individual sessions, aimed to reduce anxiety, fatigue and thought disorder by addressing the factors contributing to cognitive overload, as identified with neuropsychological examination. Evaluation took place every treatment session and at three-months follow-up, using the Outcome Rating Scale (ORS), Acceptance and Action Questionnaire–II (AAQ-II) and Emotion Regulation Questionnaire (ERQ).

Evaluation showed a positive increase in general functioning according to the ORS (average 14 % increase above the level at start of treatment), self-acceptance according to the AAQ-II (1.3 - 1.6 SD above the reported level at start of treatment), as well as the acceptance of successive follow-up treatment. However, she was unable to maintain changes in emotion-regulation strategies at follow up according to the ERQ.

In conclusion, neurocognitive evaluation enabled the individual adaptation of treatment strategies to the patient’s developmental and neurocognitive functioning and provided guidance in treatment choice, resulting in successive care. Furthermore, the patient’s inability to maintain favorable changes in emotion-regulation strategies emphasizes the need for prolonged professional guidance and support.