临床与医学基因组学杂志

Background purpose: Primary Congenital Glaucoma (PCG) is typically an autosomal recessive trait and is more prevalent in community with consanguineous marriage. The aim of current study was to screen 27 familial cases of PCG for CYP1B1, to identify and determine common mutations, and to understand its penetrance and prevalence in the Eastern provinces of Iran.

Methods: Detailed family histories up to three generations were taken, and pedigree charts were constructed. Genomic DNA was extracted from peripheral leukocytes. Primers were designed for the two coding exons of the CYP1B1 gene and the amplified products were sequenced. PolyPhen and SIFT were used to predict the functional impact of novel mutations identified in this study.

Results: Seventeen of 27 subjects (62.96%) had mutations in the CYP1B1 gene. In this study, 10 specific mutations associated with disease phenotypes were found. Six missense (p. R368H, p.E229K, p.R390C, p.V364M, p.F445I, p.G61E) and one deletion mutation (c.1504_1504delA) were previously reported and 3 missense mutations (p.L480p, p.S476P and p.R175P) were novel. The most common mutation was G61E, which was identified in 8 of 17 cases (47.05%). We also notified that one of the patients was homozygous for the mutation E229K, and also R390C (tetra-allelic).

Conclusion: Mutations in CYP1B1 was a major finding in our PCG patients. Identifying mutations in subjects at risk of developing glaucoma, particularly among relatives of PCG patients, is of clinical relevance. These findings may help in reducing the disease frequency in familial cases through proper counseling. Such studies will be of benefit in the identification of pathogenic mutations in different populations and will enable us to develop simple and rapid diagnostic tests for analyzing such cases.

Cervical Human Papillomavirus (HPV) infection in sub-Saharan Africa is among the highest in the world. HPV early proteins (E6 and E7) cause inhibition of p53 and Rb proteins respectively which are important for cell transformation. The HPV screening can be achieve using various methods like polymerase chain reaction, immunohistochemistry/ immunocytochemistry and Hybrid Capture 1/2. This study aimed at evaluating the effectiveness of some tumor markers in detecting cervical human Papillomavirus in HPV positive confirmed tissues by PCR. Fifty cervical tissue samples were subjected to nested polymerase chain reaction technique for the detection of HPV and immunohistochemistry method was used to localized and identify p53, p16 and Ki-67 antibodies. Result revealed 35(70%) expression for p16, 34(68%) for Ki-67 and 32(64%) for p53 marker in the tissue blocks studied. Nondysplastic cases expressed 62% for p16, 25% and 75% for Ki-67 and p53 respectively. Squamous Cell Carcinoma (SCC) and adenocarcinoma of the cervix showed 100 % expression for p16 gene, followed by p53 (91.6%) and Ki-67 (83.3%). Relationship between immunohistochemistry markers expression and cervical HPV using PCR was studied. Data obtained showed a 100% expression for p16, 53.8 % for Ki-67 and 30.8% for p53 tumor markers in all the HPV positive cases. HPV negative cases presented 59.5%, 67.6% and 81.7% expression for p16, Ki-67 and p53 respectively. All HPV positive cases showed statistically significant increase expression for p16 tumor marker compared with Ki-67 (P<0.001*OR=23.40) and p53 (P<0.001**, OR=41.73). These findings could be linked to retinoblastoma involvement in HPV infection which is the principle behind p16 staining reaction and therefore concluded that all HPV positive cases are p16 positive but not all p16 positive are HPV positive. We recommend p16 tumor marker as complementary test for HPV screening in poor resource centers.

Here we report a case of Hypomelanosis of Ito (HI) and de novo interstitial 15q11.2q13.3 triplication. The HI is typically associated with various chromosomal anomalies, that is why a karyotyping was selected as a first choice in genetic approach. The obtained result showed a pathological karyotype: additional material on the long arm of chromosome 15,(15)(q11q13) bands. To confirm this extra material on the long arm of chromosome 15, our subsequent step was Multiplex Ligation-dependent Probe Amplification analysis (MLPA), which detected abnormal copy numbers, corresponding to duplication, along the targeted region 15q11.2 (genes SNRPN and UBE3A). In order to further clarify the duplication boundaries the aCGH was performed, which revealed arr[GRCh37] 15q1 1.2q13.3(22,558,697-30,366,124)x4, 15q13.2q13.3(30,652,489-32,462,701)x3. As a final step we conducted segregation analysis within the family by QF-PCR of polymorphic loci to identify the origin of the chromosomal rearrangement, which turned out to be maternally inherited. Based on the results from aCGH, in our opinion the reported here chromosomal rearrangement is an interstitial triplication of chromosome 15, resulting in very rare case of tetrasomy within the targeted region of chromosome 15q. Review of the literature showed that, here we report a first genetically proven case of Hypomelanosis of Ito caused by a de novo interstitial 15q11.2q13.3 triplication.