Identification of a novel mutation of the EDA gene in X-linked hypohidrotic ectodermal dysplasia.

This study aimed to identify the disease-causing mutation in the ectodysplasin A (EDA) gene in a Chinese family affected by X-linked hypohidrotic ectodermal dysplasia (XLHED). A family clinically diagnosed with XLHED was investigated. For mutation analysis, the coding region of EDA of 2 patients and 7 unaffected members of the family was sequenced. The detected mutation in EDA was investigated in 120 normal controls. A missense mutation (c.878T>G) in EDA was detected in 2 patients and 3 female carriers, but not in 4 unaffected members of the family. The mutation was not found in the 120 healthy controls and has not been reported previously. Our findings indicate that a novel mutation (c.878T>G) of EDA is associated with XLHED and adds to the repertoire of EDA mutations.

A novel single-base deletion mutation of the RUNX2 gene in a Chinese family with cleidocranial dysplasia.

We identified a disease-causing mutation of the RUNX2 gene in a four-generation Chinese family affected with cleidocranial dysplasia (CCD). For mutation analysis, the coding region of RUNX2 was sequenced with DNA from two patients and three unaffected family members. The RUNX2 mutation was investigated in 50 normal controls by denaturing high pressure liquid chromatography. A heterozygous single-base deletion (c.549delC) of RUNX2, which predicts a termination site at the 185th codon and leads to a stop in the runt domain of RUNX2 protein, was detected in both patients but not in the three unaffected members of the family. This mutation was also not found in 50 controls and has not been reported previously. We demonstrated that a novel mutation (c.549delC) of RUNX2 is associated with CCD in a Chinese family, adding to the repertoire of RUNX2 mutations related to CCD.

Two novel NPHS1 mutations in a Chinese family with congenital nephrotic syndrome.

Congenital nephrotic syndrome of the Finnish type (CNF) is a lethal, autosomal recessive disorder mainly caused by mutations in the NPHS1 gene; it is found at a relatively high frequency in Finns. We investigated the disease-causing mutations in a Chinese family with CNF and developed a prenatal genetic diagnosis for their latest pregnancy. Mutation analysis was made of all exons and exon/intron boundaries of NPHS1 in the fetus, parents and 50 unrelated controls using PCR and direct sequencing. A heterozygous nonsense mutation within exon 20 (c.2783C>A) and a missense mutation within exon 17 (c.2225T>C) in NPHS1 were detected in the proband's father and mother, respectively, but were not found in the fetus or in 50 unrelated controls. Two novel mutations of c.2783C>A and c.2225T>C in NPHS1 were found to be causative in this Chinese CNF family with no known Finnish ancestry. The most recent sibling did not inherit these two mutations and hence was unaffected with CNF. Determining the cumulative number and ethnic distribution of known mutations can help expedite further study of the pathogenesis of CNF.