Background: Androgenetic alopecia (AGA) is a common dermatological problem, Does the
onset of the AGA matters in the general health? YKL 40 may have role in the pathogenesis of
early AGA and associated metabolic syndrome (MS). YKL 40, released by many inflammatory
cells and its biological role is not well known. Aim of the Work: The estimation of serum
level of YKL‑40 in patients with AGA to detect its role in AGA and MS pathogenesis, onset
and severity. Materials and Methods: This case–control study, 100 individuals were
enrolled in our study; 70 AGA patients and 30 healthy controls. We obtained an informed
written consent from each individual prior the participation. AGA was diagnosed clinically,
and onset was evaluated as early onset alopecia (by the age of 30 years or earlier), YKL‑40
level was measured by ELISA technique. Results: Patients showed highly significant higher
serum YKL‑40 level more than that of the healthy subjects (P < 0.001). There was highly
significant increase in YKL‑40 level among early onset male and female cases compared
to late onset cases (P < 0.001 each). There was significant increase in MS elements in
AGA cases than controls (P < 0.05), and highly significant increase in MS associations and
severity among early onset male and female cases compared to late onset cases (P < 0.001
each). AGA patients with MS showed highly significant higher serum YKL‑40 level more
than that without (P < 0.001). There was highly significant increase in YKL‑40 level among
early onset AGA with MS compared to late onset cases with MS (P < 0.001 each).
Conclusions: High serum YKL‑40 considered not only a biomarker of early onset AGA but
also considered a potential sensitive predictor for early onset MS development and severity
in patients with early onset AGA.