A familial CHARGE syndrome with a CHD7 nonsense mutation and new clinical features.

The autosomal dominant CHARGE syndrome (MIM musical sharp214800) is caused by mutations in the CHD7 gene. It is usually sporadic but a few cases with gonadal mosaicism and familial inheritance have been reported. We describe a familial CHARGE syndrome in a two-generation Finnish family with a nonsense mutation in the CHD7 gene. Detailed clinical examination of the affected family members was performed, and mutations in the CHD7 gene were analysed with direct sequencing and multiplex ligation-dependent probe amplification. A nonsense mutation, p.Q1599X, was detected in exon 21 of the CHD7 gene in three affected family members. The father was only mildly affected, whereas his son had a very severe manifestation of the syndrome, causing death at the age of 3 months. The second pregnancy was prematurely terminated in the 23rd week because of cardiac anomalies detected in the ultrasound scan. The father's brother also had mild symptoms, but no mutation was detected in him. In this report, the variability of clinical symptoms within families and the clinical importance of mildly affected patients with the CHARGE syndrome are underlined with implications for molecular genetic diagnostics of the syndrome. Features not described in the CHARGE syndrome before are also presented.