Previous reports have suggested an increased risk of cancer among patients with cartilage-hair hypoplasia (CHH). This study was carried out to further evaluate this risk among patients with CHH and their first-degree relatives.

One hundred twenty-two patients with CHH were identified through 2 countrywide epidemiologic surveys in 1974 and in 1986. Their parents and nonaffected siblings were identified through the Population Register Center. This cohort underwent follow-up for cancer incidence through the Finnish Cancer Registry to the end of 1995.

A statistically significant excess risk of cancer was seen among the patients with CHH (standardized incidence ratio 6.9, 95% confidence interval 2.3 to 16), which was mainly attributable to non-Hodgkin’s lymphoma (standardized incidence ratio 90, 95% confidence interval 18 to 264). In addition, a significant excess risk of basal cell carcinoma was seen (standardized incidence ratio 35, 95% confidence interval 7.2 to 102). The cancer incidence among the siblings or the parents did not differ from the average cancer incidence in the Finnish population.

This study confirms an increased risk of cancer, especially non-Hodgkin’s lymphoma, probably attributable to defective immunity, among patients with CHH. (J Pediatr 1999;134:315-8)