Editor—Involvement of region 3p21 of chromosome 3 in the development of Sotos syndrome is suggested by two patients who have been described. One is a Sotos syndrome patient carrying an apparently balanced translocation t(3;6)(p21;p21). The other is a non-smoking female with Sotos syndrome who died of small cell lung cancer at 22 years of age. This type of cancer is characterised by a consistent loss of heterozygosity at 3p21.3. We were able to set up an EBV immortalised lymphoblastoid cell line from a blood sample from the patient with the t(3;6) and show by fluorescent in situ hybridisation that the translocation breakpoint on the short arm of chromosome 3 does not coincide with any of the regions on this chromosome arm that have been suggested to play a role in tumour development.

In 1964 Sotos et al 1 described five children with large body size and early accelerated growth, acromegaloid features, advanced bone age, and a non-progressive neurological disorder with mental retardation. Since this report, many cases have been described of what is now known as Sotos syndrome or cerebral gigantism.2 Most cases appear to be sporadic. There are some …