18q− Syndrome: Brain MRI shows poor differentiation of gray and white matter on T2‐weighted images

Abstract

Purpose:To study brain MRI findings in patients with 18qϪ syndrome and to correlate these findings with the results of the molecular breakpoint analysis. Materials and Methods:Brain MR images of 17 patients with 18qϪ syndrome were evaluated. Segregation analysis was performed with 15 microsatellite markers to determine the deletion breakpoints and whether the deletion included the myelin basic protein (MBP) gene. Results:One patient had an interstitial deletion of 18q which spared the MBP gene. He was the only one with normal brain MRI. All 16 patients with deletions including the MBP gene had abnormal white matter in MRI. The main finding was poor differentiation of gray and white matter on T2-weighted images due to increased white matter signal intensity. In addition, measured signal intensity of the white matter was significantly increased in patients compared with controls. Conclusions:Poor differentiation of gray and white matter on T2-weighted images is the most typical MRI finding of the 18qϪ syndrome. These results support the postulation that abnormal myelination in 18qϪ syndrome is due to haploinsufficiency at or near the MBP locus.

Chromosome 18 aberrations and epilepsy: A review

“…From a pathogenetic point of view, molecular mechanisms determining epilepsy in 18qDS syndrome remain to be clarified. In fact, although epilepsy might be considered secondary to white matter dysmyelination [Loevner et al, 1996;Gay et al, 1997;Gabrielli et al, 1998;Linnankivi et al, 2003] or related to disorders of neuronal migration, which may occur in this syndrome [Alkan et al, 2002], magnetic resonance imaging (MRI) investigations resulted to be normal in the present series of patients as well as in previous reported epileptic 18q-subjects [Verrotti et al, 2003].…”

Global brain dysmyelination with above-average verbal skills in 18q - syndrome with a 17 Mb terminal deletion

“…Poor gray-and white-matter differentiation was recently described as a characteristic finding and seems to be pathognomonic to 18q) syndrome (11,12). Poor gray-and white-matter differentiation was recently described as a characteristic finding and seems to be pathognomonic to 18q) syndrome (11,12).…”

The 18q deletion syndrome and analysis of the critical region for orofacial cleft at 18q22.3

“…In most identified cases, the 18q-deletion is terminal and 5e40 Mb in size (Feenstra et al, 2007). The clinical phenotype of the 18q-syndrome is highly variable, but it is generally characterized by mild to moderate mental retardation, developmental delay (Strathdee et al, 1995;Linnankivi et al, 2006), growth hormone deficiency Ghidoni et al, 1997), craniofacial dysmorphisms (Cody et al, 1999), hearing loss (Jayarajan et al, 2000;Nuijten et al, 2003), white matter abnormalities of the brain Linnankivi et al, 2003;Häusler et al, 2005), limb anomalies, genitourinary malformations (Frizell et al, 1998), heart defects , and IgA deficiency (Dostal et al, 2007). Orofacial malformations are characteristic of the 18q-syndrome and include cleft palate with or without cleft lip (CP/L), high palate (HP) (Schinzel et al, 1975), midfacial hypoplasia, downturned corners of the mouth (Strathdee et al, 1997), prognathism, a flat nasal bridge, up-or downward-slanting palpebral fissures , malformed ears, and narrow or atretic external auditory ear canals (Schinzel et al, 1975;Nuijten et al, 2003;Dostal et al, 2006).…”