that manifests during infancy, investigators have reported.
The findings are from a cohort study published in JAMA Dermatology, which involved 107 unrelated children and adults suspected of having UHS, as well as family members, all of whom were recruited from January 2013 to December 2021. Genetic analyses were conducted in Germany from January 2014 to December 2021 with exome sequencing.
Study builds on prior research
Senior author Regina C. Betz, MD, professor of dermatogenetics at the Institute of Human Genetics, University Hospital Bonn, Germany, said that in 2016, she and her coinvestigators authored a study on the molecular genetics of UHS. That study, which involved 18 people with UHS, identified variants in three genes – PADI3, TCHH, and TGM3 – that encode proteins that play a role in the formation of the hair shaft. The investigators described how a deficiency in the shaping and mechanical strengthening of the hair shaft occurs in the UHS phenotype, which is characterized by dry, frizzy, and wiry hair that cannot be combed flat.
As a result of that previous work, “we base the assignment or confirmation of a clinical diagnosis of UHS on molecular genetic diagnostics,” the authors write in the new study, rather than on the clinical appearance of the hair and the physical examination of the patient, with confirmation on microscopical examination of the hair shaft.
Social media as instrument in finding study participants
Following the 2016 study, Dr. Betz and colleagues were contacted by many clinicians and by the public through Facebook and other social media platforms with details about possible cases of UHS, an autosomal recessive disorder. Through these contacts, blood samples, saliva, or DNA was sent to the investigators’ laboratory from 89 unrelated index patients (69 female patients, 20 male patients) suspected of having UHS. This resulted in the identification of pathogenic variants in 69 cases, the investigators write.
“In the first study, we had 18 patients, and then we tried to collect as many as possible” to determine the main mechanism behind UHS, Dr. Betz said. One question is whether there are additional genes responsible for UHS, she noted. “Even now, we are not sure, because in 25% [of cases in the new study], we didn’t find any mutation in the three known genes.”
The current study resulted in the discovery of eight novel pathogenic variants in PADI3, which are responsible for 71.0% (76) of the 107 cases. Of those, “6 were single observations and 2 were observed in 3 and 2 individuals, respectively,” the investigators write.
Children can grow out of this disorder, but it can also persist into adulthood, Dr. Betz noted. Communication that investigators had with parents of the children with UHS revealed that these children are often the targets of bullying by other children, she added.
She and her and colleagues will continue this research and are currently studying adults who have UHS.