# MOLECULAR STUDIES OF X-LINKED CHONDRODYSPLASIA PUNCTA

> **NIH NIH R01** · BAYLOR COLLEGE OF MEDICINE · 1993 · $259,587

## Abstract

While advances in molecular biology have led to better understanding
and diagnosis of many genetic diseases, many human skeletal dysplasias
remain a poorly understood group of disorders at both biochemical and
molecular levels.  This project will focus on the isolation of a murine
X-linked locus, bare patches (Bpa), which produces a complex
developmental phenotype and is likely homologous to human X-linked
dominant chondrodysplasia punctata (CDPX2).  Genetic mapping in an
interspecific backcross and physical mapping using pulsed field gel (PFG)
electrophoresis have identified loci, Gabra3 and CamLl, which flank Bpa
and are 0.8 + 0.6 cM and <3 million base pairs apart.  Overlapping yeast
artificial chromosome (YAC) clones will be isolated that span the region
to which Bpa maps using a murine YAC library prepared in the laboratory
of Dr. Shirley Tilghman.  Murine genomic clones will be isolated for
existing probes in the region.  Additional random murine probes will be
generated from mouse X:human hybrids using the polymerase chain reaction
(PCR) and DNA primers of dispersed murine repetitive sequences.  Portions
of genomic clones from the region will be sequenced to enable the design
of PCR primers to screen the murine YAC library.  The ends of YACs will
be isolated and mapped on PFGs and the interspecific backcross to develop
overlaps spanning the region between Gabra3 and CamLl.
     YACs that cosegregate with Bpa in the interspecific backcross will
be screened for conservation among species ("zoo blots") and patterns of
expression on Northern blots.  The normal and affected X chromosomes from
Bpa mice and CDPX2 females separated in somatic cell hybrids will be
examined for evidence of submicroscopic deletions which would further
localize the gene(s).  Final proof of the identity of the gene will rely
on the demonstration of the mutation in the Bpa gene or cDNA.  Once the
murine locus is cloned, studies aimed at understanding the biology of the
Bpa gene product will be initiated and attempts made to isolate the
homologous human gene.

## Key facts

- **NIH application ID:** 3159568
- **Project number:** 5R01AR039499-03
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **SAM.gov UEI:** FXKMA43NTV21
- **Principal Investigator:** Gail E. Herman
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $259,587
- **Award type:** 5
- **Project period:** 1991-07-18 → 1995-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3159568

## Citation

> US National Institutes of Health, RePORTER application 3159568, MOLECULAR STUDIES OF X-LINKED CHONDRODYSPLASIA PUNCTA (5R01AR039499-03). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3159568. Licensed CC0.

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