RESUMO
· AIM: DLAD (DnaseII-like acid Dnase) is an acid DNase that is highly expressed in human and murine lens fibre cells. Recently, the DLAD-/- mice with a deficience in DLAD gene were reported to develop nuclear cataract.To elucidate whether a deficient DLAD gene can cause some human cataract, we studied autosomal dominant nuclear catarat in 6 families and analysed linkage between cataract and DLAD locus.·METHODS: Two-point Lod score values were obtained for markers D1S551 and GATA65B07.· RESULTS: The results show negative Lod scores (z=-∞ at θ =0), so linkage was excluded between the defect and DLAD locus in these families.·CONCLUSION: no evidence for cataracts in these families linkage to chromosome 1p22.3, the DLAD locus.
RESUMO
<p><b>OBJECTIVE</b>Cleidocranial dysplasia (CCD) is a rare skeletal disease with autosomal dominant inheritance associated with mutation in RUNX 2. The authors report a Chinese girl with CCD in whom the mutation in RUNX 2 was identified.</p><p><b>METHODS</b>Clinical diagnosis was based on physical examination, radiological findings, and biochemical tests. For mutation detection, genomic DNA was extracted from peripheral blood using standard method. All 7 coding exons of RUNX 2 and their flanking intronic sequences were amplified by polymerase chain reaction (PCR), and the PCR products were then subjected to automatic DNA sequencing.</p><p><b>RESULTS</b>The affected girl showed typical clinical manifestations of CCD, including patent fontanelles, absent clavicles, short stature and dental anomalies. Direct sequencing of PCR-amplified fragments revealed a recurrent missense mutation, R190W (568 C > T), in RUNX 2. The mutation was further confirmed by Hae III restriction analysis.</p><p><b>CONCLUSION</b>A Chinese case of CCD was confirmed and the disease-causing mutation was linked to a recurrent point mutation in RUNX 2.</p>