The breakpoints occur near the 5' and 3' ends of a gene, GPC3, that spans more than 500 kilobases in Xq26; in three families, different microdeletions encompassing exons cosegregate with SGBS.
The breakpoints occur near the 5' and 3' ends of a gene, GPC3, that spans more than 500 kilobases in Xq26; in three families, different microdeletions encompassing exons cosegregate with SGBS.
The lack of correlation between the phenotype of 18 affected males from these 7 families and the location and size of the GPC3 gene mutations suggest that SGBS is caused by a nonfunctional GPC3 protein.
PCR analysis using primer pairs which amplify fragments from each of the eight exons of the GPC3 gene was carried out in a series of 18 families with SGBS (approximately half of reported cases).
It has recently been shown that the OCI-5/GPC3 gene is mutated in patients with the Simpson-Golabi-Behmel Syndrome (SGBS), an X-linked disorder characterized by pre- and postnatal overgrowth and various visceral and skeletal dysmorphisms.
The tight clustering of GPC3 and GPC4, with deletions that occasionally affect both genes, may be relevant for explaining the variability of the SGBS phenotype.
Furthermore, our finding of a GPC3 normal daughter of an SGBS carrier with skeletal abnormalities and Wilms tumour raises the possibility of a trans effect from the maternal carrier in SGBS kindreds.
However, there is still no biochemical evidence indicating that GPC3 plays such a role.Here, we report that GPC3-deficient mice exhibit several of the clinical features observed in SGBS patients, including developmental overgrowth, perinatal death, cystic and dyplastic kidneys, and abnormal lung development.
However, there is still no biochemical evidence indicating that GPC3 plays such a role.Here, we report that GPC3-deficient mice exhibit several of the clinical features observed in SGBS patients, including developmental overgrowth, perinatal death, cystic and dyplastic kidneys, and abnormal lung development.
However, there is still no biochemical evidence indicating that GPC3 plays such a role.Here, we report that GPC3-deficient mice exhibit several of the clinical features observed in SGBS patients, including developmental overgrowth, perinatal death, cystic and dyplastic kidneys, and abnormal lung development.
These results demonstrate that neither the GPC3 gene nor other genes on Xq26 are responsible for all cases of SGBS and that a second SGBS locus resides on Xp22.