Perinatal gene therapy for craniofacial dysplasia

Purpose: We aim at developing gene therapy for the perinatal treatment of genetic craniofacial anomalies. Methods: We have developed a gene therapy modality for the transfer of therapeutic genes to experimental animals, as well as patients, for the perinatal treatment of genetic anomalies utilizing a VSV-G pseudotyped Feline Immunodeficiency Virus (FIV). We are testing our treatment regime on an animal model characterized by craniofacial dysplasia, midface hypoplasia, anterior cross bite, as well as behavioral deficits and limited life span. This disorder develops secondary to excessive cellular storage of insoluble glycosaminoglycan metabolites due to targeted deletion of the b-hexosaminidase loci in mouse. This animal model closely replicates the pathophysiologic and phenotypic features of human storage diseases, such as mucopolysaccharidoses. A cardinal characteristic of this class of human and mouse disorders is that newborns display only mild features of the disease, and develop the correlate aberrant characteristics by early childhood. Therefore, we hypothesize that there is a critical perinatal window during which restoration of the genetic anomaly will resolve the underlying pathology and attenuate or prevent the clinical development of the disease. Results: We have systemically administered FIV(lacZ) to mouse pups of perinatal age (5 days old) by intraperitoneal injection. FIV(lacZ) transfers the reporter gene b-galactosidase to cultured cells and animals, and is readily detected by X-gal histochemistry and immunocytochemistry. We analyzed the expression of b-galactosidase in perinatally treated mice that were sacrificed at 3, 6, and 13 weeks after FIV(lacZ) administration. Our results demonstrate significant and stable levels of gene expression in the various organs and body structures examined. Conclusions: We have developed and tested a novel gene therapy modality that can be utilized as a platform for the development of perinatal treatment for genetic disorders.