Additional Tunisian patients with Sanjad-Sakati syndrome: A review toward a consensus on diagnostic criteria.

BACKGROUND AND OBJECTIVES: Sanjad-Sakati syndrome (SSS; OMIM 241410) is a rare autosomal recessive disorder found almost exclusively in people of Arab origin. It is characterized by congenital hypoparathyroidism, severe prenatal and postnatal growth retardation, and distinct facial dysmorphism. The molecular pathology of this syndrome was shown to be due to a mutation in the tubulin-specific chaperone E (TBCE) gene in chromosomal area 1q42-q43. We aimed to detect and confirm the common mutation responsible for SSS in Tunisian patients and review the literature in order to create a set of clinical diagnostic criteria that might provide appropriate indications for molecular testing. METHODS: Three Tunisian patients with clinical feature of SSS were examined via direct Sanger sequencing of exon 3 of the TBCE gene. RESULTS: Mutation analysis of the TBCE gene revealed the common 12-bp (155-166del) deletion in three new patients, thus raising the number of reported SSS patients to 73. Reviewing the literature, we suggest a scoring system that assigns one point each for major criteria and one half point for minor criteria. INTERPRETATION AND CONCLUSIONS: SSS is an autosomal recessive disorder found in the Middle Eastern population with an estimated incidence of 1 per 40,000-100,000 live births in Saudi Arabia. Reviewing the literature on both its clinical and biochemical characteristics, we suggest for the first time, based on defined major and minor SSS criteria, a clinical scoring system for the diagnosis of SSS. On the one hand, an established scoring system will provide appropriate indications for molecular testing and, on the other hand, reviewed data on SSS will help delineate the phenotype and draw a distinction between differential diagnoses.

MGMT methylation assessment in glioblastoma: MS-MLPA versus human methylation 450K beadchip array and immunohistochemistry

Purpose: The MGMT gene encodes a DNA repair enzyme that counteracts with chemotherapy efficiency, specifically with alkylating agents such as temozolomide (TMZ). It is well established that MGMT methylation should be screened as a predictive marker for TMZ in glioblastoma, and we thus aimed to determine a reliable and practical diagnostic method of MGMT methylation detection. Patients and methods: 55 glioblastomas were investigated for MGMT methylation status using methylation-specific multiplexed ligation probe amplification (MS-MLPA), illumina human methylation 450K BeadChip array (HM450 K) analysis, and compared to MGMT protein expression by immunohistochemistry (IHC) staining. The methylation status of promoter, intron and all MGMT CpG targeted sites were separately correlated to patient’s survival. Results: In addition to MS-MLPA and 450 K concordance, our results showed significantly higher overall survival (OS) of patients receiving TMZ and presenting MGMT methylated promoter (mean OS = 21.5 months, p = 0.046). Including all glioblastoma cases and regardless of chemotherapy, MS-MLPA showed significant survival difference between MGMT methylated and unmethylated cases (mean OS = 13, p = 0.021). Conclusion: We concluded that in glioblastoma, MGMT promoter methylation predicts TMZ sensitivity. This current comparative analysis leads to consider that MS-MLPA is a valuable as HM450 K array for MGMT methylation status screening (AU)

No disponible

MGMT methylation assessment in glioblastoma: MS-MLPA versus human methylation 450K beadchip array and immunohistochemistry.

PURPOSE: The MGMT gene encodes a DNA repair enzyme that counteracts with chemotherapy efficiency, specifically with alkylating agents such as temozolomide (TMZ). It is well established that MGMT methylation should be screened as a predictive marker for TMZ in glioblastoma, and we thus aimed to determine a reliable and practical diagnostic method of MGMT methylation detection. PATIENTS AND METHODS: 55 glioblastomas were investigated for MGMT methylation status using methylation-specific multiplexed ligation probe amplification (MS-MLPA), illumina human methylation 450K BeadChip array (HM450 K) analysis, and compared to MGMT protein expression by immunohistochemistry (IHC) staining. The methylation status of promoter, intron and all MGMT CpG targeted sites were separately correlated to patient's survival. RESULTS: In addition to MS-MLPA and 450 K concordance, our results showed significantly higher overall survival (OS) of patients receiving TMZ and presenting MGMT methylated promoter (mean OS = 21.5 months, p = 0.046). Including all glioblastoma cases and regardless of chemotherapy, MS-MLPA showed significant survival difference between MGMT methylated and unmethylated cases (mean OS = 13, p = 0.021). CONCLUSION: We concluded that in glioblastoma, MGMT promoter methylation predicts TMZ sensitivity. This current comparative analysis leads to consider that MS-MLPA is a valuable as HM450 K array for MGMT methylation status screening.

Adult recurrent pilocytic astrocytoma: Clinical, histopathological and molecular study.

BACKGROUND: PA is a grade I glial tumor that mostly occurs in children. However, although apparently similar to paediatric PA, adult PA presents a different clinical follow-up that could arise from specific molecular alterations. A variety of genetic alterations have been identified as diagnostic or prognostic glioma molecular markers. MATERIAL AND METHODS: We describe a right infratentorial tumor that occurred in a 58-year-old man. Neuroimaging and neuropathological examination suggested PA as an initial diagnosis. The tumor was completely resected. Unexpectedly, two years later, a rapidly growing tumor on the operative site was observed with a second location in the pineal region. Immunohistochemical reactions (IHC), Multiplex ligation probe amplification (MLPA) and fluorescence in situ hybridization (FISH) was performed in both primary and relapse tumor. RESULTS: Neuroimaging and neuropathological examinations suggested an unusual diagnosis for adult patients: a recurrent PA. Both MLPA and FISH analysis contribute to diagnostic confirmation by KIAA1549: BRAF fusion detection. Additional genetic results revealed interesting findings that justified the tumor aggressivity. CONCLUSION: Molecular analysis of adult PA cases should be routinely combined with histopathological and neuroimaging examination to further refine prognostic diagnoses.

Molecular diagnosis of known recessive ataxias by homozygosity mapping with SNP arrays.

The diagnosis of rare inherited diseases is becoming more and more complex as an increasing number of clinical conditions appear to be genetically heterogeneous. Multigenic inheritance also applies to the autosomal recessive progressive cerebellar ataxias (ARCAs), for which 14 genes have been identified and more are expected to be discovered. We used homozygosity mapping as a guide for identification of the defective locus in patients with ARCA born from consanguineous parents. Patients from 97 families were analyzed with GeneChip Mapping 10K or 50K SNP Affymetrix microarrays. We identified six families homozygous for regions containing the autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) gene, two families homozygous for the ataxia-telangiectasia gene (ATM), two families homozygous for the ataxia with oculomotor apraxia type 1 (AOA1) gene, and one family homozygous for the AOA type 2 (AOA2) gene. Upon direct gene testing, we were able to identify a disease-related mutation in all families but one of the two kindred homozygous at the ATM locus. Although linkage analyses pointed to a single locus on chromosome 11q22.1-q23.1 for this family, clinical features, normal levels of serum alpha-foetoprotein as well as absence of mutations in the ATM gene rather suggest the existence of an additional ARCA-related gene in that interval. While the use of homozygosity mapping was very effective at pointing to the correct gene, it also suggests that the majority of patients harbor mutations either in the genes of the rare forms of ARCA or in genes yet to be identified.