168 Chapter 10 brain properties, e.g. by white matter volume analysis or by voxel-based analysis, will improve our understanding of the pathophysiology of metopic synostosis. Finally, we may have failed to identify a difference in DTI and ASL, because we excluded syndromic trigonocephaly patients. While specific gene mutations for metopic synostosis are rare, at least 6% of these patients have cytogenetic or chromosal abnormalities.9 In literature only a minority of trigonocephaly patients develop mental retardation or borderline intellectual functioning. Van der Vlugt et al assessed IQ in 82 trigonocephaly patients. Mental retardation (IQ < 70) was present in 9 percent (n = 7) of the patients, which is elevated compared to the 2.5 percent in the general norm group. Borderline intellectual functioning (IQ 70 - 85) was present in 12 percent of the patients, which is similar to the expected 13.5 percent of the general population.5 In this study trigonocephaly patients with additional extracranial anomalies had a significantly lower IQ compared to trigonocephaly patients without extracranial anomalies. These patients with other congenital anomalies could have overlapped with syndromic cases.12 Therefore, early genetic screening of trigonocephaly patients to identify syndromic cases could be relevant for the prediction and follow-up of the neurocognitive development. Syndromic craniosynostosis Patients with syndromic craniosynostosis (sCS) show a large variation in intellectual disabilities and behavioural and emotional problems. Children with Apert syndrome or Muenke syndrome show the most cognitive, social, attentional and internalizing problems.13 Syndromic craniosynostosis patients are at high risk for ICH (9-83% for Apert, 53-64% for Crouzon, 19-43% for Saethre-Chotzen and 0-4% for Muenke syndrome).14-19 To get more understanding about the pathophysiology of these problems in syndromic craniosynostosis patients we zoomed in on the white matter architecture. In this thesis we showed that, before any surgery, young syndromic patients have no significant differences in microstructural properties compared to controls. We compared our results (n= 54, age ranges 0-2 years) with the paper on DTI results of older, operated children with sCS (n= 58, age range 6-18 years). Both papers used the same tractography protocol by Rijken et al and both papers found FOHR being a significantly associated factor.4 Rijken et al. found a similar FA in control subjects in comparison to the operated syndromic craniosynostosis patients. Diffusivity values (MD, RD and AD) of the mean white matter were significantly higher in patients compared with the control group. However, Rijken et al. did not take age into the analyses on operated craniosynostosis patients, while in pediatric DTI studies age is a significant factor for an increase in WM FA and decrease in MD.20 Also, the control group was not age matched. Therefore, it could be possible that the significant difference between craniosynostosis and controls is in fact caused by the different distribution of age
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