No abstract

Infantile hypertrophic pyloric stenosis (IHPS) is the most common form of bowel obstruction in infancy. The disease affects males four times more often than females and is considered a paradigm for the sex-modified model of multifactorial inheritance. However, pedigrees consistent with autosomal dominant inheritance have also been documented. We analyzed a 3-generation family with IHPS including 10 affected individuals (5 males and 5 females) and mapped the underlying disease locus to chromosome 16p12-p13 (LOD score 3.23) by using a single-nucleotide polymorphism-based genomewide scan. The analysis of 10 additional multiplex pedigrees yielded negative or nonsignificant LOD scores, indicating the presence of locus heterogeneity. Sequence analysis of candidate genes from the chromosome 16 disease interval excluded the presence of pathogenic mutations in the GRIN2A and MYH11 genes.

Aim-To assess the value of contrast versus plain radiography in determining radio-opaque long line tip position in neonates. Methods-In a prospective study, plain radiography was performed after insertion of radio-opaque long lines. If the line tip was not visible on the plain film, a second film with contrast was obtained in an attempt to visualise the tip. Results-Sixty eight lines were inserted during the study period, 62 of which were included in the study. In 31, a second radiographic examination with contrast was necessary to determine position of the tip. In 29 of these, the line tip was clearly visualised with contrast. On two occasions, the line tip could not be seen because the contrast had filled the vein and obscured the tip from view. Eight of the lines that required a second radiograph with contrast were repositioned. Conclusion-Intravenous contrast should be routinely used in the assessment of long line position in the neonate. (Arch Dis Child Fetal Neonatal Ed 2001;84:F129-F130)

Infantile hypertrophic pyloric stenosis (IHPS) has an incidence of 1-8 per 1000 live births and is inherited as a complex sex-modified multifactorial trait with a striking male preponderance. Syndromic and monogenic forms exist, and two loci have been identified. Infants present with vomiting due to gastric-outlet obstruction caused by hypertrophy of the smooth muscle of the pylorus. A genome-wide SNP-based high-density linkage scan was carried out on 81 IHPS pedigrees. Nonparametric and parametric linkage analysis identified loci on chromosomes 11q14-q22 (Z(max) = 3.9, p < 0.0001; HLOD(max) = 3.4, alpha = 0.34) and Xq23 (Z(max) = 4.3, p < 0.00001; HLOD(max) = 4.8, alpha = 0.56). The two linked chromosomal regions each harbor functional candidate genes that are members of the canonical transient receptor potential (TRPC) family of ion channels and have a potential role in smooth-muscle control and hypertrophy.