INSTABILITY OF LYMPHOCYTE CHROMOSOMES IN A GIRL WITH ROTHMUND-THOMSONSYNDROME

Rothmund-Thomson syndrome is a rare autosomal recessive syndrome chara cterised by poikiloderma of the face and extremities, alopecia, short stature, and skeletal defects. We report a patient with the characteri stic features of Rothmund-Thomson syndrome who also had lymphocyte chr omosome abnormalities. She has a small flat face with short palpebral fissures and micrognathia together with severe skeletal abnormalities of the upper extremities with absence of both radii, short dysmorphic ulnae, a rudimentary right thumb, and aplasia of the left thumb. She a lso has anal atresia with a rectovaginal fistula. From the age of 3 mo nths she developed poikiloderma skin changes on the face and extensor surfaces of the extremities. Mental development seems to be normal. Ly mphocyte chromosomes in the neonatal period showed an unidentified mar ker chromosome in eight of a total of 32 cells. A repeat analysis at t he age of 10 months showed three abnormal cells out of 100 analysed: 4 7,XX,- 7,+ i(7q),+ 7p, 46,XX, t(3;18)(p14.2;q22), and 49,XX, +del(3) ( p11.2), + mar, + mar. A skin biopsy from an affected area showed poor growth and five of 48 cells analysed had structural abnormalities. The father had one of 48 cells with an additional marker chromosome and t wo cells with different 7;14 translocations. The abnormal chromosome c omplements in lymphocytes indicate that there may be in vivo chromosom e instability in Rothmund-Thomson syndrome.