Minoxidil improved hair density in an Asian girl with short anagen syndrome: a case report and review of literature

Short anagen hair syndrome: association with mono- and biallelic variants in WNT10A and a genetic overlap with male pattern hair loss

BACKGROUND

Short anagen hair (SAH) is a rare paediatric hair disorder characterized by a short anagen phase, an inability to grow long scalp hair and a negative psychological impact. The genetic basis of SAH is currently unknown.

OBJECTIVES

To perform molecular genetic investigations in 48 individuals with a clinical phenotype suggestive of SAH to identify, if any, the genetic basis of this condition.

METHODS

Exome sequencing was performed in 27 patients diagnosed with SAH or with a complaint of short, nongrowing hair. The cohort was screened for variants with a minor allele frequency (MAF) < 5% in the general population and a Combined Annotation Dependent Depletion (CADD) score > 15, to identify genes whose variants were enriched in this cohort. Sanger sequencing was used for variant validation and screening of 21 additional individuals with the same clinical diagnosis and their relatives. Genetic association testing of SAH-related variants for male pattern hair loss (MPHL) was performed using UK Biobank data.

RESULTS

Analyses revealed that 20 individuals (42%) carried mono- or biallelic pathogenic variants in WNT10A. Rare WNT10A variants are associated with a phenotypic spectrum ranging from no clinical signs to severe ectodermal dysplasia. A significant association was found between WNT10A and SAH, and this was mostly observed in individuals with light-coloured hair and regression of the frontoparietal hairline. Notably, the most frequent variant in the cohort [c.682T>A;p.(Phe228Ile)] was in linkage disequilibrium with four common WNT10A variants, all of which have a known association with MPHL. Using UK Biobank data, our analyses showed that c.682T>A;p.(Phe228Ile) and one other variant identified in the SAH cohort are also associated with MPHL, and partially explain the known associations between WNT10A and MPHL.

CONCLUSIONS

Our results suggest that WNT10A is associated with SAH and that SAH has a genetic overlap with the common phenotype MPHL. The presumed shared biologic effect of WNT10A variants in SAH and MPHL is a shortening of the anagen phase. Other factors, such as modifier genes and sex, may also play a role in the clinical manifestation of hair phenotypes associated with the WNT10A locus.

Short anagen syndrome: Case series and literature review

BACKGROUND/OBJECTIVES

Short anagen syndrome is a hair cycle disorder usually diagnosed in early childhood and characterized by short hair length due to short duration of the anagen phase. The objective was to review the presentation and demographic characteristics of short anagen syndrome and compare them with the most common differential diagnosis, loose anagen syndrome.

METHODS

A retrospective review of eight children with short anagen syndrome was performed at the University of Miami Outpatient Dermatology Clinic.

RESULTS

The diagnosis of short anagen syndrome was confirmed according to clinical findings and characteristic short telogen hairs with pointed tips on the hair pull test.

CONCLUSION

This is the largest reported clinical series of short anagen syndrome thus far in the literature.