Cancer and congenital abnormalities in Asian children: a population-based study from the West Midlands.

Cancer and associated congenital abnormalities were investigated in Muslim and non-Muslim Asian children from the West Midlands. Cancer incidence rates were calculated for Indian (non-Muslim), Pakistani/Bangladeshi (Muslim) and white children diagnosed from 1978 to 1992. Incidence was significantly higher in the Pakistanis, with an age-standardised rate (ASR) of 163 cases per million per year, compared with 115 for Indian and 125 for white children. Among Asian cancer patients, congenital malformations were significantly more common in Muslim (21%) compared with non-Muslim (7%). In Muslims the malformation excess was caused by autosomal recessive and dominant disorders (in 8% and 5% of cases respectively). Cancer malformation/predisposition syndromes were found in 10% of Muslims, compared with 2% of non-Muslims. In 33% of the Muslims with malformations, childhood cancer and a malformation were also present in a close relative. None of the non-Muslims with malformations had a relative with childhood cancer. The cancer excess in Muslims may be partly related to inherited genes causing both malformations and cancer. The prevalence of autosomal recessive disorders may be related to consanguinity, which is common in the Pakistani Muslim population. The high incidence of autosomal dominant disorders may be related to older paternal age at conception, giving rise to spontaneous mutations.