Pallister-Killian Mosaic Syndrome in an Omani Newborn: A Case Report and Literature Review.

Pallister-Killian mosaic syndrome (PKS) is a rare sporadic condition with multiple congenital anomalies and intellectual deficits caused by mosaic tissue-limited tetrasomy of the short arm of chromosome 12 (12p). The clinical features are highly variable, ranging from mild to severe. Diagnosis is usually missed because of the low level of mosaicism in peripheral lymphocytes. We present a case of an Omani newborn with PKS with severe clinical presentation and multisystem involvement that lead to postnatal death. Karyotype and fluorescent in situ hybridization studies confirmed the presence of chromosome 12p duplication. This is the first case of PKS reported in the literature from Oman and the Arab world.

Cytogenetic studies of 1232 patients with different sexual development abnormalities from the Sultanate of Oman.

The aim of this study was to evaluate cytogenetic findings in Omani patients who had been referred for suspicion of sex chromosome abnormalities that resulted in different clinical disorders. Furthermore, it sought to examine the frequency of chromosomal anomalies in these patients and to compare the obtained results with those reported elsewhere. Cytogenetic analysis was performed on 1232 cases with variant characteristics of sexual development disorders who had been referred to the cytogenetic department, National Genetic Centre, Ministry of Health, from different hospitals in the Sultanate of Oman between 1999 and 2014. The karyotype results demonstrated chromosomal anomalies in 24.2% of the cases, where 67.5% of abnormalities were identified in referral females, whereas only 32.6% were in referral males. Of all sex chromosome anomalies detected, Turner syndrome was the most frequent (38.2%) followed by Klinefelter syndrome (24.9%) and XY phenotypic females (16%). XXX syndrome and XX phenotypic males represented 6.8% and 3.8% of all sex chromosome anomalies, respectively. Cytogenetic analysis of patients referred with various clinical suspicions of chromosomal abnormalities revealed a high rate of chromosomal anomalies. This is the first broad cytogenetic study reporting combined frequencies of sex chromosome anomalies in sex development disorders in Oman.

Importance of FISH combined with Morphology, Immunophenotype and Cytogenetic Analysis of Childhood/ Adult Acute Lymphoblastic Leukemia in Omani Patients.

Genetic changes associated with acute lymphoblastic leukemia (ALL) provide very important diagnostic and prognostic information with a direct impact on patient management. Detection of chromosome abnormalities by conventional cytogenetics combined with fluorescence in situ hybridization (FISH) play a very significant role in assessing risk stratification. Identification of specific chromosome abnormalities has led to the recognition of genetic subgroups based on reciprocal translocations, deletions and modal number in B or T-cell ALL. In the last twelve years 102 newly diagnosed childhood/adult ALL bone marrow samples were analysed for chromosomal abnormalities with conventional G-banding, and FISH (selected cases) using specific probes in our hospital. G-banded karyotype analysis found clonal numerical and/or structural chromosomal aberrations in 74.2% of cases. Patients with pseudodiploidy represented the most frequent group (38.7%) followed by high hyperdiploidy group (12.9%), low hyperdiploidy group (9.7%), hypodiploidy (<46) group (9.7%) and high hypertriploidy group (3.2%). The highest observed numerical chromosomal alteration was high hyperdiploidy (12.9%) with abnormal karyotypes while abnormal 12p (7.5%) was the highest observed structural abnormality followed by t(12;21)(p13.3;q22) resulting in ETV6/RUNX1 fusion (5.4%) and t(9;22)(q34.1;q11.2) resulting in BCR/ABL1 fusion (4.3%). Interestingly, we identified 16 cases with rare and complex structural aberrations. Application of the FISH technique produced major improvements in the sensitivity and accuracy of cytogenetic analysis with ALL patients. In conclusion it confirmed heterogeneity of ALL by identifying various recurrent chromosomal aberrations along with non-specific rearrangements and their association with specific immunophenotypes. This study pool is representative of paediatric/adult ALL patients in Oman.

Cytogenetic studies in couples with recurrent miscarriage in the Sultanate of Oman.

Miscarriage, defined as spontaneous pregnancy loss at <20-28 weeks' gestation, is a common clinical problem. Balanced chromosomal rearrangements in either parent are an important cause of repeated pregnancy loss, particularly in the first trimester. In this study, chromosomal abnormalities that cause recurrent miscarriage were evaluated in Omani parents and some of their dysmorphic children. A total of 380 couples (760 individuals) with two or more recurrent miscarriages were examined for chromosomal aberrations during the period 1999-2006. For each proband the chromosomal preparations were analysed and karyotyped after applying a Giemsa-trypsin banding method. The overall incidence of chromosomal anomaly was 26 out of 760 individuals (3.42%). These abnormalities included 21 (2.8%) structural aberrations and 5 (0.7%) numerical anomalies. In addition to these abnormalities, 39 (5.1%) chromosomal variants were also found. The nature of these abnormalities and their relation to obstetric history are discussed. In conclusion, chromosomal abnormality is one of the causes of recurrent miscarriage. This study illustrates the incidence and distribution of chromosomal abnormalities among Omani couples with recurrent miscarriage. Cytogenetic findings could provide valuable information for genetic counselling and allow monitoring of future pregnancies by prenatal diagnosis in couples with a history of recurrent miscarriage.