SQSTM1 mutation: Description of the first Tunisian case and literature review.

BACKGROUND: Mutations in SQSTM1 gene have been recently identified as a rare cause of progressive childhood neurodegenerative disorder. So far, only 25 patients from 10 unrelated families were reported. METHODS AND RESULTS: We report on the first Tunisian case of an 11-year-old girl with cerebellar ataxia, chorea and ophthalmoparesis. Brain MRI was normal. Whole-exome sequencing revealed a homozygous mutation c.823_824del(p.Ser275Phefs*17) in SQSTM1 gene (GenBank: NM_003900.4). CONCLUSION: By pooling our data to the data of literature, we delineated the phenotypic spectrum and stressed on genetic heterogeneity of this rare neurodegenerative disease.

Monte Carlo dose calculation in presence of low-density media: Application to lung SBRT treated during DIBH.

PURPOSE: Commercial algorithms used in Radiotherapy include approximations that are generally acceptable. However their limits can be seen when confronted with small fields and low-density media. These conditions exist during the treatment of lung cancers with Stereotactic Body Radiation Therapy (SBRT) achieved with the "Deep Inspiration Breath Hold" (DIBH) technique. A Monte Carlo (MC) model of a linear accelerator was used to assess the performance of two algorithms (Varian Acuros and AAA) in these conditions. This model is validated using phantoms with different densities. Lastly, results for SBRT cases are compared to both Acuros and AAA. METHODS: A Varian TrueBeam linac was modeled using GATE/Geant4 and validated by comparing dose distributions for simple fields to measurements in water and in heterogeneous phantoms composed of PMMA and two types of cork (corresponding to lung densities during free-breathing and DIBH). Experimental measurements are also compared to AAA and Acuros. Finally, results of Acuros/AAA are compared to MC for a clinical case (SBRT during DIBH). RESULTS: Based on 1D gamma index comparisons with measurements in water, the TrueBeam model was validated (>97% of points passed this test). In heterogeneous phantoms, and in particular for small field sizes, very low density (0.12g.cm-3) and at the edge of the field, MC model was still in good agreement with measurements whilst AAA and Acuros showed discrepancies. With the patient CT, similar differences between MC and AAA/Acuros were observed for static fields but disappeared using an SBRT arc field. CONCLUSIONS: Our MC model is validated and limits of commercial algorithms are shown in very low densities.

Pyridoxine-dependent epilepsy: A novel mutation in a Tunisian child.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive metabolic disease characterized by seizures in neonates or infants, which is unresponsive to antiepileptic drugs but controlled by pyridoxine. Without prompt treatment, continued seizures and severe encephalopathy result. Mutations in the ALDH7A1 gene encoding α-amino-adipic semialdehyde (α-AASA) dehydrogenase (antiquitin) have been identified as the cause of PDE. We report on a novel ALDH7A1 mutation in a Tunisian child with PDE.

Immunological changes in opportunistic parasitic infections.

This study was done on 110 patients with different types of malignant diseases and 20 healthy controls. Cases were divided into four groups according to parasitological and serological examination. The first group included 37 patients without any parasitic infection, the second 28 patients with no opportunistic parasitic infection, the third group 33 patients with opportunistic parasitic infection while the fourth included 12 patients with mixed opportunistic and non opportunistic parasites. Immunological status was estimated by carrying out leucocyte migration inhibition test and intradermal skin test for cell mediated immunity and quantitative determination of immunoglobulins IgG, IgM and IgA for humoral immunity testing. It was found that cell mediated immunity was decreased in cancer patients compared with the normal control group. Super added parasitic infections lead to greater decrease. Opportunistic parasitic infection aggravated the condition more. Marked suppression of the cell mediated immunity was found in the group of cancer patients with mixed opportunistic and non opportunistic parasitic infections. IgG and IgA were increased in the first three groups and decreased in the mixed one, IgM was increased in the first and second groups while decreased in groups with opportunistic infections.

Parasitological and bacteriological studies in recurrent diarrhoea in patients with chronic liver diseases.

Sixty patients with chronic liver disease complaining of persistent or recurrent diarrhoea where studied. The stools were examined by direct smear, formol ether concentration method and modified Ziehl Neelsen technique for Cryptosporidium in addition to stool cultures for enteric pathogenic bacteria as Salmonella, Shigella and E. coli. Giardia lamblia was the most prevalent pathogen responsible for diarrhoea in 23.3% of cases followed by Entamoeba histolytica in 21.6%, Schistosoma mansoni in 5% and Hymenolepis nana and Ascaris lumbricoides in 1.6%. Concerning bacteria, Salmonella was detected (10%), Shigella (6.7%) and E. coli (13.3%). In conclusion, Cryptosporidium was not a cause of diarrhoea in patients with chronic liver disease.