[Biochemical studies on familial neuroblastoma].

According to the two-mutation model of neuroblastoma several investigations were performed in order to find the gene carrier in a family with familial neuroblastoma. The results of these former studies are as follows: 1. Neither chromosomal analyses of the peripheral blood nor the examinations of catecholamines nor of cystathionine in the urine could mark the first step to neuroblastoma. 2. Since cystathioniuria was not only seen in blood-relations but also in relatives by marriage and since vitamin B6 deficiency was revealed, cystathioninuria was interpreted as secondary to vitamin B6 deficiency. In this study the normal values of cystathioninuria and vitamin B6 supply were examined. Furthermore the effect of oral vitamin B6 loading on cystathioninuria and oxaluria in familial neuroblastoma was investigated and the vitamin B6 supply in the neighbours of the family was analysed. The results permitted the following conclusions: 1. In 46 of 58 children and adults cystathioninuria was found in an immeasurable range by column chromatography. Only in 12 persons it could be measured quantitatively. With the exception of 6 explanable elevations no value exceeded 20 mumol/24 hr. These results show that the acceptance of the limiting value of 20 mumol/24 hr for increased cystathioninuria is justified. 2. Vitamine B6 deficiency was found in two of 7 patients. In one child this could be explained by the underlying disease. This finding supports the suggestion that vitamine B6 deficiency can relative frequently observed. 3. The examinations of cystathioninuria and oxaluria before and after loading with vitamine B6 showed different results. Whereas oxaluria decreased after loading cystathioninuria was not surely influenced. 4. The neighbours of the members with familial neuroblastoma showed mostly a reduced vitamine B6 supply. This fact could be an indication of exogenous reason of vitamine B6 deficiency in familial neuroblastoma.