Mutational analysis of GSC, HOXA2 and PRKRA in 106 Chinese patients with microtia

Microtia is defined as a developmental malformation characterized by a small, abnormal shaped auricle, with atresia or stenosis of the auditory canal. Genes responsible for nonsyndromic microtia have remained elusive. We therefore report a mutational analysis of GSC, HOXA2 and PRKRA in 106 congenital microtia patients without any combined malformation to explore the relationship between GSC, HOXA2, PRKRA and nonsyndromic microtia.

A total of 106 patients with a clinical diagnosis of congenital microtia and a control group (100 unaffected controls) were recruited through the Eye and ENT Hospital of Fudan University in China. Genomic DNA was extracted following a standard protocol. DNA sequencing analysis was performed in all exons and the exon-intron borders of GSC, HOXA2 and PRKRA.

We identified 5 genomic variants in GSC, HOXA2 and PRKRA. As to the GSC, we obtained a reported variant g.994C > T in exon 2, which resulted in no change of protein. Our results revealed that g.994C > T was also detected in 10 control cases. We also detected 2 novel variants, g.90G > A and g.114A > C, in the 5'UTR of HOXA2. No class 5 or 4 genomic variant of PRKRA was identified in our microtia patients. Additionally, two previously reported SNVs in GSC and PRKRA were also presented.

We suggest that g.994C > T is a new SNV, which is different from the previous report. Further study is needed to prove the function of 2 novel variants in the 5'UTR of HOXA2, and to explore the possible mechanism of these variants in the occurrence of microtia.