Recessive Mutations in POLR3B Encoding RNA Polymerase III Subunit Causing Diffuse Hypomyelination in Patients with 4H Leukodystrophy with Polymicrogyria and Cataracts.

The diagnosis of 4H leukodystrophy (hypomyelination, hypogonadotropic hypogonadism, and hypodontia) is based on clinical findings and magnetic resonance imaging (MRI). Recently, mutations of the genes encoding Pol III (RNA polymerase III) subunit A (POLR3A) and subunit B (POL3B) have been identified as the genetic causes of hypomyelination. We describe two Polish female siblings aged 5 and 10 years with compound heterozygous mutations in POLR3B. They both presented with similar clinical symptoms and MRI findings presenting as 4H leukodystrophy, and the association of polymicrogyria and cataract. According to our observation in young children with the absence of hypogonadotropic hypogonadism, brain MRI pattern is very essential in proper early diagnosis of 4H leukodystrophy. All clinical and radiological results are of course helpful, however genetic conformation is always necessary.

[Benign tectal tumors: clinical and neuroradiological correlations]. / Lagodne guzy pokrywy sródmózgowia w materiale wlasnym.

Benign tectal tumours in children constitute a distinct group of brainstem gliomas, characterised by a usually benign clinical course. The aim of this paper was a retrospective analysis of 1) results of conservative treatment, 2) diagnostic value of CT and MRI and 3) correlation of the MR image with the clinical course of the disease. Our material includes 15 patients aged from 6 to 16. The treatment consisted in the implantation of a CSF-shunting device (6 children), endoscopic ventriculostomy (6 children) or ventriculostomy in a child with malfunction of a previously implanted shunt (3 cases). Follow-up periods range from 3 to 219 months (mean 46.8 mo.). A slight progression of tumour in imaging studies was noted in 3 cases, while in the remaining patients neither clinical nor radiologic progression of the disease was observed. There was no correlation between tumour size and focal contrast enhancement in MRI and the natural course of the disease. The method of choice in the diagnosis of benign tectal tumours is MRI and in the treatment of associated hydrocephalus-endoscopic third ventriculostomy. An in-depth diagnostic work-up and a more aggressive cause-oriented treatment is used only in cases of a documented clinical and radiological progression.

Proton MR Spectroscopy in Patients with Leigh Syndrome.

The aim of the present study was to evaluate MRS findings in patients with Leigh syndrome. We report our results of HMR spectroscopic studies performed in six patients (aged four months to ten years) with clinically proved Leigh syndrome. All examinations were done with 1.5 T scanner using an eight-channel phased array head coil. HMRS data were obtained using 2D-chemical shift imaging (CSI) and SVS sequences with short (30 ms) and long (135 ms) echo time. The MR spectra were acquired in multiple voxel localized in deep gray matter and periventricular white matter. The results were compared to the control group data. In most of our patients we found bilateral lesions in the basal ganglia and brain stem. HMRS data revealed elevated lactate in the affected areas, significantly diminished NAA/Cr ratio. The relatively high Cho/Cr ratio in the gray and white matter was also noted. HMRS is an important tool for non-invasive brain tissue analysis in Leigh syndrome.