Trisomy 8 is a condition where every cell of an individual presents with an extra copy (three copies of chromosome 8. This disorder occurs when a pair of chromosomes fails to divide evenly, which results in cells containing more than two of this chromosome. Here, we report a case of mosaic trisomy 8 in a Malaysian Malay boy.Although patient in this case confirmed with T8M, he exhibited few of the characteristic features that previously were reported to be associated with T8M. However, the patient’s very young age might explain the lack of clinical presentation of these features.
Emanuel syndrome, also referred to as supernumerary der(22) or t(11;22) syndrome, is a rare genomic syndrome. Patients are normally presented with multiple congenital anomalies and severe developmental disabilities. Affected newborns usually carry a derivative chromosome 22 inherited from either parent, which stems from a balanced translocation between chromosomes 11 and 22. Unfortunately, identification of Emanuel syndrome carriers is diffi- cult as balanced translocations do not typically present symptoms. We identified two patients diagnosed as Emanuel syndrome with identical chromosomal aberration: 47,XX,+der(22)t(11;22)(q24;q12.1)mat karyotype but presenting variable phenotypic features. Emanuel syndrome patients present variable phenotypes and karyotypes have also been inconsistent albeit the existence of a derivative chromosome 22. Our data suggests that there may exist ac- companying genetic aberrations which influence the outcome of Emanuel syndrome phenotypes but it should be cautioned that more patient observations, diagnostic data and research is required before conclusions can be drawn on definitive karyotypic-phenotypic correlations.
A 31-year-old lady with normal physical characteristics was found to have persistent high FSH and LH and was suspected possible premature ovarian failure after reported to have not normal menstrual cycle. Leucocytes were collected from patient’s fresh peripheral blood sample and Giemsa banding (G-banding) was done. All metaphases were captured and analysed using Cytovision software 4.5 and the final analysis show 47,XXX.
Advanced parental age is a risk factor for chromosomal abnormalities in their offspring. Trisomy X or Triple X syn- drome has previously been reported with advanced maternal age. Here we report two (2) cases of Trisomy X with paternal age as risk factor. Generally, Trisomy X individuals show variable physical and psychological manifesta- tions. However, both cases reported here have advanced paternal age as a risk factor; 55 years old (46 years old at conception) for Case 1 with patient having right eye squint, beaked nose, Posterior Misalignment Type Ventricular Septal Defect (PMVSD) and small Patent Ductus Arteriosus (PDA) with failure to thrive and 49 years old (45 years old at conception) for Case 2 with speech delay and protruding tongue. In view of that, advanced paternal age could possibly contribute the accumulation of de novo mutations in germ line mosaicism.
Chromosomal abnormalities (CA) can affect numerical or structural compositions of chromosomosal DNA leading to a diversity of clinical phenotypic presentations. Awareness of prenatal diagnosis and genetic counselling have improved with advancing medical research but CA remain prevalent as its aetiology is unknown. The objective of this study is to determine the frequencies of various CA in the principle region of north-western Malaysia and compare this data to previous reports to ascertain if statistical differences exist. Karyotype analyses performed at the Genetics Laboratory, Advanced Diagnostic Laboratory (ADL) during the first 5-years of cytogenetic services, totalling 1461 cases, were assessed in this report. Cases suspected of CA were initially diagnosed by clinicians and detailed clinical and family histories were recorded. Peripheral blood lymphocytes of patients were collected and cultured in vitro for acquisition of karyotype by standardized G-banding technique. Fluorescence in situ hybridization (FISH) was conducted in cases suspected of to be DiGeorge, Prader-Willi, Angelman and Williams syndrome. Of the total samples (1805) received and cultured, 1669 (92.46%) successfully yielded results. Abnormal outcomes were observed in 495 cases (29.66%) whereby pronounced majority of cases 299 (68.42%) were Down syndrome. This is followed by Edward, Turner and Patau syndrome, in order of frequency. Numerical CA appears to be prevalent accounting for 85.86% of cases. Structural CA accounted for 14.14% of total positive cases whereby the most common was deletions (34.29%) followed by translocations (20%), ring chromosomes (5.71%), Fragile X syndrome (4.29%), duplications (5.71%) and marker chromosomes (7.14%). The remainder of cases (22.86%) consisted of derivative chromosomes and other complex aberrations. The number of polymorphic variant cases were 27 (1.62%). The number of peripheral blood samples received has significantly increased from 14.3 per month in 2006 to 32.17 per month in 2011. Comparative analysis of our study to previous reports reveal statistical differences in the occurrence of several CA including Edward, Patau, Klinefelter and Fragile-X syndrome. Our experience with peripheral blood samples for cytogenetic analysis demonstrated a success rate of 92.46%. This showed an increase in clinicians validating patients’ diagnoses with karyotyping which is essential in confirming genetic anomalies with the goal to substantiate genetic counselling.