Platelet parameters in children with chromosome 22q11 deletion and conotruncal heart defects.

BACKGROUND AND OBJECTIVES: The 22q11 deletion syndrome is associated with a wide spectrum of phenotypic features, hence clinical diagnosis is difficult. Individuals with this syndrome are found to have a risk of developing transfusion associated graft-versus-host reaction, if they are given nonirradiated blood. Our aim was to elucidate whether chromosome 22q11 deletion in children with syndromic conotruncal heart defects is associated with platelet abnormality. MATERIALS AND METHODS: The genetic analysis was performed by standard cytogenetic and Fluorescence in situ hybridization technique. The platelet parameters in 39 patients with chromosome 22q11 deletion were compared with 154 cases without deletion. RESULTS: In deletion versus no deletion group, the mean of mean platelet volume (MPV) was 10.5 ± 2.5 vs 7.6 ± 1.5 fL, platelet count was 225 ± 80.7 and 339 ± 127.3 × 10 9 /L and frequency of high MPV was 49% vs 7% (P < .0001). The MPV was associated with a sensitivity of 90.9% and a specificity of 79.6% at a cutoff value of 8.32 fL, (area under the ROC curve 91%). A nonsignificant negative correlation was found between MPV and platelet count (r = -0.152; P = .361) in children with deletion. CONCLUSION: A cutoff value of 8.32 fL for MPV can be an indicator of high risk of chromosome 22q11 deletion in individuals with syndromic conotruncal defects. Individuals with chromosome 22q11 deletion should be given irradiated blood especially during cardiac surgery. Further investigation should clarify the etiology behind variation in frequency of high MPV in different conotruncal lesions.

Cardiac spectrum, cytogenetic analysis and thyroid profile of 418 children with Down syndrome from South India: a cross-sectional study.

OBJECTIVE: To describe the spectrum of congenital heart disease in children with Down syndrome and their cytogenetic profile (and that of parents of those with translocation), and thyroid profile. METHODS: A cross sectional study was conducted in 418 consecutive patients with Down syndrome attending the Department of Pediatric Genetics from a tertiary care centre in Kerala with a comprehensive Pediatric Cardiac Program, from November 2005 through April 2012. All children were offered cytogenetic analysis and were subjected to echocardiography. Parental karyotyping was offered for children with translocation type of Down syndrome. The thyroid profiles of all children were checked at the first visit and once every 6 mo during follow up. RESULTS: Congenital heart disease was present in 256 (63.4 %) of 404 children with Down syndrome. Ventricular septal defect (72; 28.1 %) was the commonest, followed by atrio-ventricular septal defect (70; 27.3 %) and patent ductus arteriosus (43; 16.8 %). Surgical correction was accomplished in 104 (40.6 %) with excellent intermediate-term outcomes. Three hundred eighty seven of 418 children (92.6 %) underwent cytogenetic tests. The abnormalities included non-disjunction (340, 87.8 %), translocation (33, 8.5 %) and mosaicism (12, 3.1 %). Hypothyroidism was detected in 57 children (13.6 %). CONCLUSIONS: The prevalence of congenital heart disease in children with Down syndrome in Kerala is the highest reported (63.4 %). Ventricular septal defect is the most common heart disease in the present study. The results highlight the changing attitudes of families towards the surgical correction of congenital heart disease in children with Down syndrome. Prevalence of hypothyroidism in Down syndrome in Kerala is 13.6 %.

Turner syndrome and its variants.

Case records of female patients with karyotype proven turner syndrome were analyzed. 11 patients had classic Turner karyotype (Group 1) and 13 patients had karyotype suggestive of one of the variants of Turner syndrome (Group 2). There was a median difference of 3 years between the age of presentation and the age of diagnosis in Group 2. Out of the thirteen patients in Group 2, 4 had no clinical stigmata of Turner Syndrome; the rest (n=9) had one or more of the typical clinical stigmata of Turner Syndrome. One patient with a complex mosaic karyotype also had an intracranial medulloblastoma. One patient in each group had coarctation of the aorta. 5 patients in Group 1 and 3 patients in Group 2 had primary hypothyroidism and received levothyroxine. The median Thyroid Stimulating Hormone levels were significantly higher among patients in group 1 than in group 2.

Partial trisomy 9q due to maternal 9q 17q translocation.

Partial Trisomy 9q is a unique chromosomal anomaly with a distinctive phenotype. Only 5 cases have been reported in the literature till now. A large family with four affected children was studied in detail and was compared with the five previously reported cases. Determination of this novel balanced translocation in their family had helped us to offer prenatal diagnosis. This presentation is unique as even though partial trisomy 9q has been reported earlier with 9/17 translocations, our family is the first to have a translocation between q arms of chromosomes 9 and 17.