Abstract: Objective: To report a Chinese Han family with hereditary hypotrichosis simplex caused by APCDD1 gene mutation. Methods: The epidemiological and clinical data were collected. Genomic DNA was extracted from peripheral blood of the family members, and genomic DNA samples from 100 unrelated healthy Han people were selected as controls. All exons and flanking sequences of APCDD1, RPL21, SNRPE and CDSN genes were amplified by PCR, and Sanger sequencing was used to detect potential gene mutations. Results: There were 5 generations in this family, including 13 patients and 22 normal cases. All patients were born with normal hair, then began to develop progressive hair loss and slow hair growth, sparse body hair, normal eyebrows and eyelashes. DNA was extracted only from 8 patients and 4 normals of this family for gene mutation detection. There was a recurrent heterozygous mutation of C.26 T>G（p.Leu9Arg）in APCDD1 gene, which was not found in unaffected individuals of the family and 100 healthy controls. For the other three genes, RPL21, SNRPE and CDSN, no sequence variants were detected in all members of the family. Conclusion: The heterozygous mutation of C.26 T>G（p.Leu9Arg） in APCDD1 gene may be the genetic cause of hereditary hypotrichosis simplex in this family.

Key words: hereditary hypotrichosis simplex, hypotrichosis 1, APCDD1 gene, mutation