Array-CGH analysis in Rwandan patients presenting development delay/intellectual disability with multiple congenital anomalies.

BACKGROUND: Array-CGH is considered as the first-tier investigation used to identify copy number variations. Right now, there is no available data about the genetic etiology of patients with development delay/intellectual disability and congenital malformation in East Africa. METHODS: Array comparative genomic hybridization was performed in 50 Rwandan patients with development delay/intellectual disability and multiple congenital abnormalities, using the Agilent's 180 K microarray platform. RESULTS: Fourteen patients (28%) had a global development delay whereas 36 (72%) patients presented intellectual disability. All patients presented multiple congenital abnormalities. Clinically significant copy number variations were found in 13 patients (26%). Size of CNVs ranged from 0,9 Mb to 34 Mb. Six patients had CNVs associated with known syndromes, whereas 7 patients presented rare genomic imbalances. CONCLUSION: This study showed that CNVs are present in African population and show the importance to implement genetic testing in East-African countries.

A new 48, XXYY/47, XYY syndrome associated with multiple skeletal abnormalities, congenital heart disease and mental retardation.

While the XYY and XXYY syndromes have been several time described in patients, the combination of both syndromes in an individual is a rare event and may result in a severe phenotype. In the present observation, a boy with congenital scoliosis due to segmented thoracic hemivertebra associated with radioulnar synostosis and congenital heart disease is described. Chromosome G-banding and FISH analysis demonstrated a de novo mosaic karyotype 48, XXYY/47, XYY in this patient. To the best of our knowledge, this is the first report of a combination of XYY and XXYY syndromes.

Pattern of congenital heart diseases in Rwandan children with genetic defects.

INTRODUCTION: Congenital heart diseases (CHD) are commonly associated with genetic defects. Our study aimed at determining the occurrence and pattern of CHD association with genetic defects among pediatric patients in Rwanda. METHODS: A total of 125 patients with clinical features suggestive of genetic defects were recruited. Echocardiography and standard karyotype studies were performed in all patients. RESULTS: CHDs were detected in the majority of patients with genetic defects. The commonest isolated CHD was ventricular septal defect found in many cases of Down syndrome. In total, chromosomal abnormalities represented the majority of cases in our cohort and were associated with various types of CHDs. CONCLUSION: Our findings showed that CHDs are common in Rwandan pediatric patients with genetic defects. These results suggest that a routine echocardiography assessment combined with systematic genetic investigations including standard karyotype should be mandatory in patients presenting characteristic clinical features in whom CHD is suspected to be associated with genetic defect.

Systematic chromosomal aberrations found in murine bone marrow-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are studied as a cellular source for the treatment of various diseases. In this work, we isolated and cultivated murine bone marrow-derived MSCs. After a first observation of a solid tumor in a mouse injected with these cells, we systematically explored their chromosomal stability. We observed in all the cytogenetically analyzed cases gross chromosomal alterations every time the MSCs went through the senescence crisis while the lymphocytes from the same animals showed a normal chromosome count. This observation was confirmed in different mouse strains, with different culture protocols, and even in short-term cultures after a hematopoietic cell negative immunodepletion performed in order to accelerate the isolation procedure. Therefore, we conclude that murine MSCs display high chromosomal instability and can generate tumors, and that care must be taken before using them for the evaluation of MSC therapeutic potential.