Method for the determination of data for the preparation of the diagnosis of phakomatosis

A method for determining whether an offspring of an individual afflicted with neurofibromatosis has an increased risk of developing neurofibromatosis comprising the steps of:

• a) making available tumor material of the afflicted individual,
• b) making available blood of the afflicted individual,
• c) isolating the tumor DNA from the tumor material of the afflicted individual,
• d) isolating the blood DNA from the blood of the afflicted individual,
• e) amplifying one or more polymorphous DNA microsatellite markers for neurofibromatosis genes from the tumor material,
• f) amplifying the one or more polymorphous DNA microsatellite markers from the blood,
• g) separating by amount and length the polymorphous DNA microsatellite markers from the tumor material,
• h) separating by amount and length the polymorphous DNA microsatellite markers from the blood,
• i) observing the amount and length of the polymorphous DNA microsatellite markers from the tumor material,
• j) observing the amount and length of the polymorphous DNA microsatellite markers from the blood,
• k) determining an allele that is lost in the tumor material,
• l) amplifying the polymorphous DNA microsatellite markers from the blood of an offspring of the afflicted individual;
• and
• m) determining which allele of the afflicted individual was inherited by the offspring based on steps (k) and (l), wherein inheritance of the allele retained in the tumor indicates an increased risk of developing neurofibromatosis.