A Case of Cleidocranial Dysplasia with a Novel Mutation and Growth Velocity Gain with Growth Hormone Treatment

Cleidocranial dysplasia (CCD) is a rare congenital autosomal dominant skeletal disorder that is characterized by hypoplasia or aplasia of clavicles, failure of cranial suture closure, dental anomalies, short stature and other changes in skeletal patterning and growth. The gene responsible for pathogenesis has been mapped to the short arm of chromosome 6p21, core binding factor alpha-1 (CBFA1) or runt related transcription factor-2 (RUNX2). Here we describe a CCD patient with a novel mutation in the RUNX2 gene. A five-and-a-half year old girl presented with severe short stature, dysmorphic facial appearance (hypertelorism, prominent forehead, high palate, midfacial hypoplasia), macrocephaly, large anterior fontanelle, increased anteroposterior chest diameter. Her shoulders were close to each other and her bilateral clavicles appeared short on physical examination. Bilateral hypoplastic clavicles, coxa valga, hypoplasia of iliac bones, wide symphysis pubis and phalangeal dysplastic features were detected on her skeletal X-ray examination. She was diagnosed as having CCD. Molecular analysis detected a novel heterozygous mutation 'NM_001024630.3p.T155P(c.463A > C)' in the RUNX2 gene. At age seven years and two months old, because of her severe short stature, growth hormone (GH) treatment was started and she responded well to GH therapy with no adverse effects. In conclusion, hypoplasia or aplasia of the clavicles, failure of cranial suture closure, dental anomalies and short stature should bring CCD to mind. We present a novel mutation in the RUNX2 gene for CCD. We obtained growth velocity gain with GH treatment in our patient.