A case of Adams-Oliver syndrome associated with c.3190_3191del and c.4491 + 1G > T mutations in the DOCK6 gene

Background

Adams–Oliver syndrome (AOS [MIM 100300]) is a rare, multiple malformation syndrome commonly characterized by scalp aplasia cutis congenita (ACC) and transverse terminal limb defects (TTLD). Brain abnormalities and heart defects are also present in most patients. Both autosomal-dominant and autosomal-recessive inheritance of the disease have been observed. To date, six causative genes have been identified: ARHGAP31, DOCK6, EOGT, RBPJ, NOTCH1, and DLL4. Autosomal-recessive mutations are mostly associated with DOCK6 (MIM: 614219) and EOGT (MIM: 615297), while mutations in ARHGAP31 (MIM: 100300), RBPJ (MIM: 614814), NOTCH1 (MIM: 616028), and DLL4 (MIM: 616589) have been linked to autosomal-dominant inheritance.

Case

We report a case of AOS caused by DOCK6 mutations (c.3190_3191del and c.4491 + 1G > T), showing no signs of scalp ACC or TTLD, but with bilateral ventricular dilation and ophthalmic abnormalities. Results of whole-exome high-throughput sequencing were analyzed using a combination of pathogenicity prediction algorithms, query of variant databases, and review of the literature. Candidate gene variation sites were identified for pedigree verification.

Conclusions

The correlation between the genotype and phenotype of AOS has great variability, and the specific pathogenesis of AOS remains to be further studied.