# LOCALIZATION OF X-LINKED HYPOPHOSPHATEMIC RICKETS GENE

> **NIH NIH K11** · BOSTON CHILDREN'S HOSPITAL · 1994 · $78,300

## Abstract

X-linked hypophosphatemic rickets (XLHR) is the most common inherited
form of rickets. XLHR is an X-linked dominant disorder since
heterozygous females are also affected. There is a great deal of
variability in the expression of XLHR. This project is based upon the
hypothesis that there are a number of different mutations, including
deletions, among individuals with XLHR. The overall goal of this project
is to further characterize the XLHR locus, and to identify the gene that
is abnormal in this disease.

The XLHR gene locus has been mapped to X(p22.1-p22.2). The aim of Phase
I of this project is to develop a detailed (1cM resolution) physical map
of this region and to begin to identify mutations in affected
individuals. Markers spanning the X(p22.1-p22.2) region will be
generated from an X chromosome library, and will be ordered using pulsed
field gel electrophoresis. Large deletions in affected individuals will
be identified, if present, using the map. If no large deletions are
identified, tighter linkage of the markers generated to the XLHR locus
will be established using traditional RFLP techniques.

The aim of Phase II of this project is to identify the abnormal gene in
XLHR. If a deletion is found in one or more affected patients, the
search for the gene will begin in that region. If no deletions are
detected, a jumping library will be generated consisting of CpG-rich
areas, regions of putative gene transcription. Chromosomal walking will
proceed from these regions to localize the XLHR gene. In order to verify
that a given DNA sequence could be a candidate gene, the sequence will
be hybridized against mammalian DNA from several different species, to
tissue-specific RNA, and to tissue-specific CDNA libraries. The long-
range goal is to characterize the function of the XLHR gene and its
protein product.

## Key facts

- **NIH application ID:** 2194423
- **Project number:** 5K11HD000961-03
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **SAM.gov UEI:** Z1L9F1MM1RY3
- **Principal Investigator:** INGRID A HOLM
- **Activity code:** K11 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $78,300
- **Award type:** 5
- **Project period:** 1992-07-01 → 1997-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2194423

## Citation

> US National Institutes of Health, RePORTER application 2194423, LOCALIZATION OF X-LINKED HYPOPHOSPHATEMIC RICKETS GENE (5K11HD000961-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2194423. Licensed CC0.

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