Group members
Howard Henderson	Medical Scientist
Sandra Pienaar	PhD student

 

THE GENETIC BASIS OF RESISTANCE OR SUSCEPTABILITY TO MTB IN CHILDREN: Mutations in candidate genes of the IFNg pathway.

Team: PhD project of Sandra Pienaar, supervisors Prof Howard Henderson and Dr Brian Eley. This is part of a large Wellcome funded collaborative project with Prof Michael Levin, Dept Paediatrics, Imperial College, London on “Childhood Tuberculosis: Identification of the molecular immunological basis of Susceptibility and resistance to mycobacterial infection”

The interferon gamma pathway has been shown to be critical for the cell mediated immune response to turberculosis. Numerous genes are active in this pathway and are thus candidates for genetic influence of the effectiveness of this pathway. This project focuses on one of these genes (IL-12p40) and specifically concentrates on the promoter region.  The initial objective was to search for sequence variations in the promoter region which may influence gene expression and thus levels of IL-12 synthesised and secreted by immune cells. Initially, 164 children were selected from the Wellcome TB cohort for screening; this cohort included children with TB and healthy controls.  The promoter region was amplified by PCR using 8 overlapping primer pairs, and each amplicon screened for sequence alterations by the transgenomic WAVE technique. A single base change (A—>G) was found at base -1515  This mutation was observed more frequently in controls than in the patient cohort (8.3% in controls vs 0.08% in TB cases, with p= 0.016), which may suggest that it offers protection against TB infection.  A PCR assay using the ARMS principle has been set up to detect this mutation, with the total number of children now screened being 297.  Although the A—>G substitution occurs fairly deep within the promoter region, it does lie in the rare oligonucleotide repeat GTATA , which has been reported to be important for binding nuclear proteins.  These DNA data are augmented by clinical information and cytokine levels (TNFa, IFNg and IL12), which have been documented on all the subjects screened.  This project will now determine the biological significance of this promoter mutation through the use of luciferase reporter assays.

 

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RECENT PUBLICATIONS

VAN DER WATT GF, ELEY B, HENDERSON H.
Whole blood mitochondrial DNA depletion in South African HIV-infected children.
Journal of Paed Biochem. 2010; in press

BAUMGARTEN I, LEISEGANG F, HENDERSON H.
Glutaric aciduria type 1 in South Africa-high incidence of glutaryl-CoA dehydrogenase deficiency in black South Africans.
Mol Genet Metab. 2010 Oct-Nov;101(2-3):178-82.

GARMANY TH, WAMBACH JA, HEINS HB, WATKINS-TORRY JM, WEGNER DI, BENNET K, AN P, LAND G, HENDERSON HE, NOGEE LM, COLE F, AARON H.
Population and disease-based prevalence of the common mutations associated with surfactant deficiency.
Pediatric Research 2008 Jun;63(6):645-9.

MCBEE AD, WEGNER DJ, CARLSON CS, WAMBACH JA, YANG P, HEINS HB, SAUGSTAD OD, TRUSGNICH MA, WATKINS-TORRY, NOGEE LM, HENDERSON HE, COLE S, AARON H.
Recombination as a mechanism for sporadic mutation in the surfactant protein-C gene.
Pediatric Pulmonology 2008 May;43(5):443-50.

POUWELS ED, BLOM DJ, FIRTH JC, HENDERSON HE, MARAIS AD.
Severe hypertriglyceridemia as a result of familial hyperchylomicronaemia: the Cape Town experience.
S Afr Med J 2008 Feb;98(2):105-8

PARHAM KL, ROBERTS A, THOMAS A, WURZNER R, HENDERSON HE, POTTER PC, MORGAN BP, ORREN A.
Prevalence of mutations leading to complete C6 deficiency (C6Q0) in the Western Cape, South Africa and detection of novel mutations leading to C6Q0 in an Irish family.
Molecular Immunology 2007; 44: 2756 - 60

SWARTZ L, LEISEGANG F, OWEN EP, HENDERSON HE.
An OTC deficiency “phenocopy” in association with Klinefelter syndrome.
J Inher Met Dis 2007: 30; 101

ABERA AB, MARAIS AD, RAAL FJ, LEISEGANG F, JONES S, GEORGE P, HENDERSON HE.
Autosomal recessive hypercholesterolemia; Discrimination of ARH protein and LDLR function in the homozygous FH Phenotype.
Clin Chemica Acta 2007: 378; 33-37

WILMSHURST J, LEISEGANG F, HENDERSON HE.
Genetic testing for spinal muscular atrophy.
S Afr Med J 2006: 96; 1216

NICOL MP, PIENAAR D, WOOD K, ELEY B, WILKINSON RJ, HENDERSON H, SMITH L, SAMODIEN S, BEATTY D.
Enzyme-linked immunospot assay responses to early secretory antigenic target 6, culture filtrate protein 10, and purified protein derivative among children with tuberculosis: implications for diagnosis and monitoring of therapy.
Clin Infect Dis. 2005 ;40:1301-8.

COULTER-MACKIE M, APPLEGARTH D, TOONE J, HENDERSON HE. 
The major allele of the alanine:glyoxylate aminotransferase gene: seven novel mutations causing type 1 primary hyperoxaluria.
Mol Genet Met 2004, 82;64-68

TENA GN, YOUNG DB, ELEY B, HENDERSON H, NICOL MP, LEVIN M, KAMPMANN B.
Failure to control growth of mycobacteria in blood from children infected with human immunodeficiency virus and its relationship to T cell function.
J Infect Dis. 2003 ;187:1544-51

COULTER_MACKIE MB, TUNG A, HENDERSON HE, TOONE JR, APPLEGARTH DA. 
The AGT gene in Africa: a distinctive minor allele haplotype, a polymorphism (V3261I), and a novel PH1 mutation (A112D) in black Africans.
Mol Genet Met 2003, 78;44-50

HENDERSON HE, LEISEGANG F, BROWN R, ELEY B.
The clinical and molecular spectrum of galactosaemia in patients from the Cape Town region of South Africa.
BMC paediatrics 2002, 2:7

PETERSON J, AYYOBI AF, MA Y, HENDERSON H, REINA M,DEEB SS, SANTAMRINA-FOJO S, HAYDEN MR, BRUNZELL JD.
Structural and functional consequences of missense mutations in exon 5 of the lipoprotein lipase gene.
J Lipid Res. 2002: 43; 398-406

WILMSHURST J, REYNOLDS L, VAN TOORN R, LEISEGANG F, HENDERSON HE.
Spinal Muscular Atrophy in Black South Africans: concordance with the universal SMN1 genotype.
Clin Genet. 2002, 62:165-8

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