SALL4 and NFATC2: two major actors of interstitial 20q13.2 duplication.

Interstitial duplication within the long arm of chromosome 20 is an uncommon chromosome structural abnormality. We report here the clinical and molecular characterization associated with pure 20q13.2 duplication in three unrelated patients. The most frequent clinical features were developmental delay, facial dysmorphism, cardiac malformation and skeletal anomalies. All DNA gains occurred de novo, ranging from 1.1 Mb to 11.5 Mb. Compared with previously reported conventional cytogenetic analyses, oligonucleotides array CGH allowed us to refine breakpoints and determine the genes of interest in the region. Involvement of SALL4 in cardiac malformations and NFATC2 gene disruption in both cardiac and skeletal anomalies are discussed.

Is long-term virological response related to CCR5 Delta32 deletion in HIV-1-infected patients started on highly active antiretroviral therapy?

OBJECTIVE: The aim of the study was to determine whether the chemokine (C-C motif) receptor 5 (CCR5) Delta32 deletion is associated with long-term response to combination antiretroviral treatment (cART) in HIV-1-infected patients. METHODS: The genetic substudy of the Agence Nationale de Recherche sur le SIDA (ANRS) CO8 APROCO-COPILOTE cohort included 609 patients who started protease inhibitor-containing cART in 1997-1999. Patients were considered to have a sustained virological response if all plasma HIV RNA measurements in the period considered were <500 HIV-1 RNA copies/ml, allowing for a single blip. Virological response was compared between patients heterozygous for CCR5 Delta32 (Delta32/wt) and wild-type patients (wt/wt) from month 4 to year 3 and from month 4 to year 5. Logistic regression analysis was used to adjust for baseline demographical data, HIV RNA, CD4 cell count, antiretroviral exposure status, time spent on antiretroviral therapy at years 3 and 5 and adherence to treatment (month 4 to year 3 or 5). RESULTS: A sustained virological response was more frequent in Delta32/wt than in wt/wt patients from month 4 to year 3, with 66%vs. 52% of patients, respectively, showing a sustained response (P=0.02); after adjustment for potential confounders, the association of Delta32 with a sustained response was nearly significant (P=0.07). A sustained virological response was also more frequent in Delta32/wt patients up to year 5, with 48% showing a sustained response vs. 35% of wt/wt patients (P=0.01); after adjustment, Delta32 remained significantly associated with a sustained virological response up to year 5 (P=0.04). There was no association with CD4 response. CONCLUSION: The Delta32 deletion in Delta32/wt patients is associated with a beneficial virological response to cART in the long term. Whether this association is a direct effect of the Delta32 deletion remains unclear and requires confirmation in further observational studies.

The contribution of germline rearrangements to the spectrum of BRCA2 mutations.

BACKGROUND: Few germline BRCA2 rearrangements have been described compared with the large number of germline rearrangements reported in the BRCA1 gene. However, some BRCA2 rearrangements have been reported in families that included at least one case of male breast cancer. OBJECTIVE: To estimate the contribution of large genomic rearrangements to the spectrum of BRCA2 defects. METHODS: Quantitative multiplex PCR of short fluorescent fragments (QMPSF) was used to screen the BRCA2 gene for germline rearrangements in highly selected families. QMPSF was previously used to detect heterozygous deletions/duplications in many genes including BRCA1 and BRCA2. RESULTS: We selected a subgroup of 194 high risk families with four or more breast cancers with an average age at diagnosis of < or = 50 years, who were recruited through 14 genetic counselling centres in France and one centre in Switzerland. BRCA2 mutations were detected in 18.6% (36 index cases) and BRCA1 mutations in 12.4% (24 index cases) of these families. Of the 134 BRCA1/2 negative index cases in this subgroup, 120 were screened for large rearrangements of BRCA2 using QMPSF. Novel and distinct BRCA2 deletions were detected in three families and their boundaries were determined. We found that genomic rearrangements represent 7.7% (95% confidence interval 0% to 16%) of the BRCA2 mutation spectrum. CONCLUSION: The molecular diagnosis of breast cancer predisposition should include screening for BRCA2 rearrangements, at least in families with a high probability of BRCA2 defects.

32-nucleotide deletion, associated with defence against hiv/aids, is a predominant mutation of CCR5 gene in the population of Georgia.

There is a special interest to investigate genetic peculiarities in the populations with a low HIV seroprevalence. Despite of presence of high-risk conditions for rapid spread of HIV/AIDS epidemics in Georgia, the prevalence of this infection in the country remains very low. We studied polymorphisms of CCR5 gene in Georgians. Blood samples from 190 women randomly selected from the cohort of pregnant women involved in the program of prevention of mother-to-child HIV transmission in Georgia have been investigated. Two-step PCR was used to amplify the whole CCR5 genetic sequence. Detection of mutations and polymorphisms was done by dHPLC. All samples showing specific patterns by dHPLC, were sequenced to identify the exact nature of the mutation. It was shown that CCR5-delta32 mutation is a predominant alteration of CCR5 gene among Georgians. All subjects bearing this mutation were heterozygotes. Frequency of delta32 CCR5 allele in the population of Georgia was equal to 5%. Only one case of R223Q mutation and two cases of mutations in the non-coding region of CCR5 gene were also found. Our findings differ from the existing data showing the absence of the CCR5-delta32 mutation among Georgians and provide further support to the hypothesis on a Northeastern European origin of this mutation and North to South gradient of its distribution.