LINKAGE ANALYSIS OF INFANTILE PYLORIC-STENOSIS AND MARKERS FROM CHROMOSOME 9Q11-Q33 - NO EVIDENCE FOR A MAJOR GENE IN THIS CANDIDATE REGION

A genetic component in the actiology of infantile pyloric stenosis (PS ) is well established. Segregation analysis is compatible with a multi factorial sex modified threshold model of inheritance but a major gene of low penetrance has not been excluded. PS has been reported to occu r in 57% (four of seven) of cases with duplication of chromosome 9q11- q33. Twenty families with PS were studied using genetic markers at loc i D9S55, D9S111, D9S15, D9S12, D9S56, D9S59, and ASS from this region of chromosome 9. Pairwise lod scores of - 2 were obtained with all the se markers at recombination fractions greater or equal to 0.04 under b oth autosomal dominant and autosomal recessive models of inheritance. This provides evidence against the existence of a major locus predispo sing to PS within chromosome 9q11-q33.