Isolated follicle stimulating hormone deficiency

What it is

From: Orphanet

A rare congenital hypogonadotropic hypogonadism characterized by hypogonadism due to selective deficiency of follicle stimulating hormone (FSH). Clinical manifestations are primary amenorrhea, absent or incomplete breast development, and infertility in women, and small testes, azoospermia, and infertility in men. Luteinizing hormone is elevated in the gonadotropin-releasing hormone stimulation test, while the FSH response is impaired.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Decreased serum estradiol · Very frequent (99-80%)

A reduction below normal concentration of estradiol in the circulation.

Decreased testicular size · Very frequent (99-80%)

Reduced volume of the testicle (the male gonad).

Delayed menarche · Very frequent (99-80%)

First period after the age of 15 years.

Delayed puberty · Very frequent (99-80%)

Passing the age when puberty normally occurs with no physical or hormonal signs of the onset of puberty.

Delayed skeletal maturation · Very frequent (99-80%)

A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.

Female hypogonadism · Obligate (100%)

Decreased functionality of the female gonads, i.e., of the ovary.

Gonadotropin deficiency · Obligate (100%)

A reduced ability to secrete gonadotropins, which are protein hormones secreted by gonadotrope cells of the anterior pituitary gland, including the hormones follitropin (FSH) and luteinizing hormone (LH).

Hypogonadotropic hypogonadism · Very frequent (99-80%)

Hypogonadotropic hypogonadism is characterized by reduced function of the gonads (testes in males or ovaries in females) and results from the absence of the gonadal stimulating pituitary hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Male hypogonadism · Obligate (100%)

Decreased functionality of the male gonad, i.e., of the testis, with reduced spermatogenesis or testosterone synthesis.

Sparse axillary hair · Very frequent (99-80%)

Reduced number or density of axillary hair.

Sparse pubic hair · Very frequent (99-80%)

Reduced number or density of pubic hair.

Decreased serum testosterone concentration · Very frequent (99-80%)

Primary amenorrhea · Very frequent (99-80%)

Abnormal sperm morphology · Frequent (79-30%)

A structural anomaly of sperm.

Other findings in the same source

From: Orphanet

Additional reported features include Azoospermia (Frequent (79-30%)); Bilateral breast hypoplasia (Frequent (79-30%)); Decreased female libido (Frequent (79-30%)); Hyperplasia of the Leydig cells (Frequent (79-30%)); Oligomenorrhea (Frequent (79-30%)); Oligozoospermia (Frequent (79-30%)); Testicular atrophy (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adolescent; Adult

Inheritance in the source

From: Orphanet

Autosomal recessive

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal recessive pattern usually involves disease-causing changes in both copies of a gene. Parents may each carry one altered copy without having the condition themselves. A genetic counsellor can explain carrier testing and reproductive implications using the actual laboratory findings, rather than the condition name alone.

Which doctor should you see?

The suggested department for discussing Isolated follicle stimulating hormone deficiency is Endocrinology, with a endocrinologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which hormone or metabolic finding is important in this case?
• How should test timing and current medicines be taken into account?
• What follow-up would show whether the care plan is working?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Isolated follicle stimulating hormone deficiency. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.