Kallmann syndrome (KS), also known as hypogonadotropic hypogonadism (HH) or olfactory-gonadal dysplasia, is a genetic condition in which the primary symptom is a failure to begin puberty or a failure to fully complete it. It occurs in both males and females and has the additional symptoms of hypogonadism and almost invariably infertility. The condition has a low prevalence that is estimated to be 1 in 4000 for male HH cases overall and 1:50000 for KS. It is three to five times more common in males than females. Whether this is a true sex imbalance or a reflection of how difficult KS/HH is to diagnose correctly in males vs females has yet to be fully established.This article reports a 26-year-old male presenting with delayed puberty. The synthetic decapeptide luteinizing hormone-releasing hormone stimulation test showed that the secretion levels of follicle-stimulating hormone and luteinizing hormone were delayed. The eigengenes commonly associated with idiopathic HH (IHH) were screened, and an X-linked recessive (KAL-1) mutation was found. His gonadotropin and testosterone levels increased significantly after pulsatile gonadotropin-releasing hormone (GnRH) subcutaneous therapy by pump. A relevant literature review on the recent advances in the diagnosis and treatment of KS and genetic counseling was conducted.KS is caused by a KAL-1 mutation that follows an X-linked recessive inheritance pattern. Pulsatile GnRH subcutaneous therapy by pump was effective in this patient.©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.