Identifying candidate genes for X-linked hypophosphatemic rickets (HYP) in the critical region X(p22.1-p22.2)
- Harvard Medical School, Boston, MA (United States); and others
X-linked hypophosphatemic rickets (HYP) is the most common inherited form of rickets, characterized by a proximal renal tubular phosphate leak leading to phosphate-wasting and abnormal 1.25-dihydroxyvitamin D metabolism. The primary defect is unknown, and the candidate gene approach has thus far been unsuccessful in identifying the gene. The HYP locus has been mapped to X(p22.1-p22.2) and more recently to a 500,000 base pair region spanned by two YACs, E01138 and A0472. In an effort to identify the HYP gene in the 500 kb region, we are taking the direct selection approach. Since the tissue expressing the HYP gene is unknown, we are using cDNA libraries from a number of tissues for direct selection, including kidney, liver, thyroid, brain, spinal cord, total fetus, bone, and an osteosarcoma cell line. The tissue cDNA is hybridized to the YACs A0472 and EO1138 (obtained courtesy of Fiona Francis, Imperial Cancer Research Fund, London) in the presence of quenchers, which block repeated and ribosomal sequences on the YACs. A selected library is created from the tissues cDNAs that hybridize to the YACs. The selected cDNA library is first screened to eliminate inserts containing repeated and ribosomal sequences. The presence of the inserts on the YAC and on X(p22.1-p22.2) is then verified using mapping panels. Candidate cDNAs that make it through this analysis are sequenced. Our first attempts at making selected libraries resulted in a number of contaminants. Three separate libraries are currently under construction, using the following combinations of tissue cDNA libraries: (1) kidney, liver, and thyroid; (2) brain, spinal cord, and total fetus; and (3) bone and an osteosarcoma cell line. We will discuss transcripts obtained from these libraries.
- OSTI ID:
- 134419
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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