Trisomy 9 mosaicism in a child with a tethered cord

A two and a half-year-old girl was diagnosed with trisomy 9 mosaicism that was detected in 22% of skin fibroblasts but was not evident in blood. This child manifests some clinical features not previously reported in trisomy 9 mosaicism including a thoracic syringomyelia and a tethered cord due to an extradural lipoma with intradural involvement. DNA analysis showed that she did not have uniparental disomy in her dominant disomic cell line.