Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
DermFocus, University of Bern, Bern, Switzerland.
Anim Genet. 2023 Aug;54(4):562-565. doi: 10.1111/age.13319. Epub 2023 Mar 26.
Ichthyoses represent a heterogeneous group of cornification disorders that are associated with skin barrier defects. We investigated a 9-month-old Chihuahua showing excessive scale formation. Clinical and histopathological examinations revealed non-epidermolytic ichthyosis and a genetic defect was suspected. We therefore sequenced the genome of the affected dog and compared the data with 564 genetically diverse control genomes. Filtering for private variants identified a homozygous missense variant in SDR9C7, c.454C>T or p.(Arg152Trp). SDR9C7 is a known candidate gene for ichthyosis in humans and encodes the short-chain dehydrogenase/reductase family 9C member 7. The enzyme is involved in the production of a functional corneocyte lipid envelope (CLE), a crucial component of the epidermal barrier. Pathogenic variants in SDR9C7 have been described in human patients with autosomal recessive ichthyosis. We assume that the identified missense variant in the affected Chihuahua of this study impairs the normal enzymatic activity of SDR9C7 and thus prevents the formation of a functioning CLE, resulting in a defective skin barrier. To the best of our knowledge, this is the first report of a spontaneous SDR9C7 variant in domestic animals.
鱼鳞病是一组角化障碍性疾病，与皮肤屏障缺陷有关。我们研究了一只 9 个月大的吉娃娃，它表现出过度的鳞屑形成。临床和组织病理学检查显示非表皮松解性鱼鳞病，怀疑存在遗传缺陷。因此，我们对受影响的狗进行了基因组测序，并将数据与 564 个具有遗传多样性的对照基因组进行了比较。通过筛选个体变异，在 SDR9C7 中发现了一个纯合错义变异，c.454C>T 或 p.(Arg152Trp)。SDR9C7 是人类鱼鳞病的已知候选基因，编码短链脱氢酶/还原酶家族 9C 成员 7。该酶参与功能性角质细胞脂质包膜 (CLE) 的产生，这是表皮屏障的关键组成部分。SDR9C7 的致病性变异已在常染色体隐性鱼鳞病的人类患者中被描述。我们假设本研究中受影响的吉娃娃中的鉴定错义变异会损害 SDR9C7 的正常酶活性，从而阻止形成功能正常的 CLE，导致皮肤屏障缺陷。据我们所知，这是首例在 家畜中发现的 SDR9C7 自发变异。
