Tinea Imbricata, Susceptibility To

Tinea imbricata (TI) produces a superficial skin infection with unmistakable clinical appearance. It is a chronic disorder common in parts of Papua New Guinea and Oceania. It has also been reported in Mexico and South America. A familial pattern suggested to Serjeantson and Lawrence (1977) autosomal recessive inheritance of susceptibility. In married couples, no concordance beyond that expected by chance was observed and segregation in different types of matings was compatible with recessive inheritance. Ravine et al. (1980) analyzed 228 pedigrees from a Papua New Guinea population and concluded that autosomal recessive inheritance is likely. The frequency of the susceptibility gene was estimated to be 0.49. The possibility of autosomal dominant inheritance with reduced penetrance could not be excluded. The causative fungus is Trichophyton concentricum. The significance of inherited susceptibility is indicated by the fact that although the disease is found extensively throughout the tropics, it is absent from Africa and northern Australia. Workers have observed a much higher prevalence in some races than in others living in the same country under closely related environmental circumstances.