CHARACTERIZATION OF A CYTOGENETIC 17Q11.2 DELETION IN AN NF1 PATIENT WITH A CONTIGUOUS GENE SYNDROME

We report on a rare patient screened as a putative carrier of a contig uous gene syndrome on the basis of a complex phenotype characterized b y sporadic neurofibromatosis type 1 (NF1), dysmorphism, mental retarda tion and severe skeletal anomalies. A cytogenetically visible 17q11.2 deletion was detected in the patient's karyotype by high-resolution ba nding and confirmed by fluorescence in situ hybridization with yeast a rtificial chromosomes targeting the NF1 region. Analysis of the segreg ation from parents to probound of 13 polymorphic DNA markers, either c ontiguous or contained within the NF1 gene, showed that the patient is hemizygous at sites within the NF1 gene - the AAAT-Alu repeat in the 5' region of intron 27b, the CA/GT microsatellite in the 3' region of intron 27b, and the CA/GT microsatellite in intron 38 - and at the ext ragenic D17S798 locus, distal to the 3' end of NF1. The patient may be an important resource in the identification of genes downstream of NF 1 that may contribute to some of his extra-NF1 clinical signs.