Brain Imaging Early diagnosis of the<unk>  can be determined by brain imaging. Magnetic resonance imaging (MRI) of the brain of<unk>  patients have revealed significant abnormalities. Abnormal gyration patterns were seen, including polymicrogyria; many unusually small folds in the brain, simplified gyria; reduced number and shallow appearance of gyri, and periventricular nodular heterotopia; failure of neurons to migrate properly during early development of the fetal brain. Ventriculomegaly can also be observed in MRI where the lateral ventricles become dilated in the foetus and can contribute to developmental delays in<unk>  individual. Another common feature observed in<unk>  patients is Arnold-Chiari malformations which are structural defects in the cerebellum that manifest during fetal development and can lead to vision problems, scoliosis or kyphosis in<unk>  patients. Other pathological features seen on MRI scans of<unk>  individuals include arachnoid cysts, hypoplasia of the corpus callosum and cerebellar hemispheres and loss of periventricular white matter. Most individuals with<unk>  are identified early in childhood due to developmental delays and intellectual disabilities. However, a formal diagnosis of intellectual disability can only be conducted by a performance of an IQ test score of below 70. Whole Exome Sequencing Whole exome sequencing (WES) can be used as a non-biased tool in the diagnostic evaluation of individuals with suspected genetic disorders such as the<unk> . Using WES, individuals were identified with truncating variants of SON and overlapping clinical features.<unk>  has been identified as a neurodevelopmental disorder associated with a de novo mutation in the SON gene using WES. The SON gene is known to be a major cause of severe intellectual disability and consequent developmental disorders. The first de novo truncating variant in SON was recognised in a group of individuals with severe intellectual disabilities. Sanger sequencing or the use of WES of parental samples confirmed the de novo status of the truncating and missense mutations of the SON gene in the sampled<unk>  individuals. Variants identified included a premature stop variant in exon 3, frame-shift variants in exon 3 and a frameshift variant in exon 4.
ZTTK syndrome
ATR-16 syndrome
CAMFAK syndrome
ATR-X syndrome
Treacher Collins syndrome
MEDNIK syndrome
GRACILE syndrome
LIG4 syndrome