Chromosome 22 microdeletion in children with syndromic congenital heart disease by fluorescent in situ hybridization (FISH)

Congenital heart diseases (CHDs) are the most common of all birth defects. Congenital heart disease may occur as an isolated malformation or may be part of a syndrome. One of the most common syndromes associated with CHDs is the 22q11.2 microdeletion syndrome, the various conditions associated with del22q11 include DiGeorge syndrome (DGS), velocardiofacial syndrome (VCFS), conotruncal anomaly face syndrome (CTAFS), and others. The abnormalities associated with this syndrome include parathyroid hypoplasia, thymic hypoplasia, immune defect, cleft palate, and abnormal facies. The cardiac defects are usually derived from conotruncus. The aim of the study was to detect the prevalence and the most common or frequent clinical manifestations of chromosome 22q11.2 microdeletion among children with syndromic congenital heart disease. The study was conducted on 20 children with syndromic CHD presenting to the Menoufiya University Hospitals, Egypt. Their ages ranged from 10 days to 12 years. Cytogenetic study and fluorescence in situ hybridization (FISH) were performed in the patients. The study revealed that 2 patients were with chromosomal aberrations [one with 46,XY, add (13)(p13) & the other with 47,XX,+13]. In addition, FISH revealed 4 patients (20%) with 22q11.2 microdeletion syndrome. The congenital heart malformations detected in patients with 22q11.2 microdeletion were somewhat unexpected and included VSD, ASD, PDA, and double outlet right ventricle. The most frequent extracardiac features were hypocalcemia, microcephaly, brain atrophy, epicanthus, low set posteriorly rotated ears, micrognathia, and anemia. The extracardiac features were in some cases subtle. It is concluded that 22q11.2 microdeletion is not uncommon and its manifestations are highly variable. This entails that screening for the microdeletion by FISH should be performed in all patients with syndromic CHD especially those with hypocalcemia, microcephaly, brain atrophy, epicanthus, low set ears, posteriorly rotated ears, micrognathia, and anemia. In addition, patients with minor features and those with non-conotruncal heart disease should not be excluded from the screening for 22 microdeletion.Keywords: Chromosome 22 microdeletion; Syndromic congenital heart disease; DiGeorge syndrome; Hypocalcemia; Velocardiofacial syndrom

Non HLA genetic markers association with type-1 diabetes mellitus

The currently available data identified IDDM1 and IDDM2 as 2 susceptibility loci for type 1 diabetes (T1D). The major histocompatibility complex (MHC)/HLA region referred to as IDDM1 contains several 100 genes known to have a great influence on T1D risk. Within IDDM2, a minisatellite variable number of tandem repeats (VNTR) locus in the insulin gene (INS) promoter region is likely to represent the etiologic polymorphism. The aim of the present work was to study the association between genotypes and susceptibility to T1D among Egyptian diabetic children and their family members. Twenty-five nuclear Egyptian families with 27 children having T1D, aged 3–14 years, their nondiabetic 44 sibs, aged 3–15 years and their parents were included in our study. All studied children were subjected to: detailed history and family pedigree. Thorough clinical examination and anthropometric measurements. Laboratory work up of diabetes including random blood sugar (RBS) and HbA1C. Molecular genetics of INS was studied in four steps; nucleic acid purification, amplification, sequencing and haplotyping using flanking single nucleotide  polymorphisms (SNPs) as surrogate markers for minisatellite alleles identification. Analysis of variant repeat distribution among Egyptian families combined with flanking haplotypes revealed that all our diabetic children had class I alleles of INS; 9 had class IC+, 9 had classID+ and 9 had class ID, while all non-diabetic family members had class III alleles of INS. Therefore the three class I alleles were considered to be equally predisposing to T1D, while class III alleles are dominantly protective. There was significant positive correlations between body massindex (BMI) and both HbA1C and AST liver enzyme among diabetic children with class IC+ but not other alleles; indicating that they need close monitoring of their diabetic control and liver functions beside following specific dietary regimens. It can be concluded that all class I alleles (IC+, ID+ and ID) are equally important susceptibility factors for T1D among Egyptian children, while class III alleles (IIIA and IIIB) are dominantlyprotective. It is concluded also that our diabetic children with class IC+ are an especially endangered subgroup of diabetics. Genotyping for INS-VNTR alleles is recommended for diabetic children as an important step of diagnostic and follow up regimens and for their non-diabetic familymembers for family counseling and early identification of potential diabetics. Further studies of INS-VNTR alleles and HLA haplotypes all over Egypt are recommended to define the Egyptian susceptibility loci for T1D and their relations to the clinical and laboratory findings as an importantnational programs

Delaying surgery for patients with a previous SARS-CoV-2 infection

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