[Diagnosis of multiple endocrine neoplasms type IIa using DNA analysis]

The gene causing MEN IIa has recently being assigned to the pericentromeric region of chromosome 10. We performed linkage analysis using DNA-markers closely related to the chromosomal locus at chromosome 10: MCK II, retinol binding protein cDNA and cTBIRBP-9. Available for the study were EDTA blood from two families. The analysis was positive in two asymptomatic offsprings in one family (B), whereas the markers were not informative in the other family (A). Genetic distance of the informative marker of family A to MEN IIa gene is 2 cM, i.e. a likelihood of 98% (95% up a confidence limit with 5%) for the gene carrier status of two children aged 11 and 7 y old. The following clinical investigation including pentagastrin test, plasma catecholamines and 24 hour urine catecholamines and parathormone was negative until now. We recommend early linkage analysis for establishing the genetic status in offspring of MEN IIa families to focus further screening to those, who are predicted to be gene carrier.