Autosomal recessive hypophosphatemic rickets

What it is

From: Orphanet

A rare, autosomal recessive renal phosphate-wasting disorder characterized by childhood-onset hypophosphatemia that clinically manifests with rickets and/or osteomalacia, slow growth/short stature, bone pain and skeletal deformities. Additional findings may include fatigue, muscle weakness and repeated bone fractures.

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.

Abnormal trabecular bone morphology · Very frequent (99-80%)

Abnormal structure or form of trabecular bone.

Abnormality of renal excretion · Very frequent (99-80%)

An altered ability of the kidneys to void urine and/or specific substances.

Abnormality of the lower limb · Very frequent (99-80%)

An abnormality of the leg.

Abnormality of vitamin D metabolism · Very frequent (99-80%)

Concentration of vitamin D or a vitamin D metabolite in the blood circulation outside of normal limits.

Bone pain · Very frequent (99-80%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to bone.

Coxa vara · Very frequent (99-80%)

Coxa vara includes all forms of decrease of the femoral neck shaft angle (the angle between the neck and the shaft of the femur) to less than 120 degrees.

Delayed eruption of teeth · Very frequent (99-80%)

Delayed tooth eruption, which can be defined as tooth eruption more than 2 SD beyond the mean eruption age.

Distal femoral bowing · Very frequent (99-80%)

A bending or abnormal curvature of the distal portion of the femur.

Elevated alkaline phosphatase of bone origin · Very frequent (99-80%)

An abnormally increased level of bone isoforms of alkaline phosphatase, tissue-nonspecific isozyme in the blood.

Genu varum · Very frequent (99-80%)

A positional abnormality marked by outward bowing of the legs in which the knees stay wide apart when a person stands with the feet and ankles together.

Growth delay · Very frequent (99-80%)

A deficiency or slowing down of growth pre- and postnatally.

Hyperphosphaturia · Very frequent (99-80%)

An increased excretion of phosphates in the urine.

Increased bone mineral density · Very frequent (99-80%)

An abnormal increase of bone mineral density, that is, of the amount of matter per cubic centimeter of bones which is often referred to as osteosclerosis. Osteosclerosis can be detected on radiological examination as an increased whiteness (density) of affected bones.

Low serum calcitriol · Very frequent (99-80%)

The concentration of calcitriol in the blood circulation is below the lower limit of normal.

Other findings in the same source

From: Orphanet

Additional reported features include Lower limb asymmetry (Very frequent (99-80%)); Osteomalacia (Very frequent (99-80%)); Renal hypophosphatemia (Very frequent (99-80%)); Renal phosphate wasting (Very frequent (99-80%)); Sclerotic vertebral endplates (Very frequent (99-80%)); Sensorineural hearing impairment (Very frequent (99-80%)); Short stature (Very frequent (99-80%)); Skeletal dysplasia (Very frequent (99-80%)); Enlargement of the wrists (Very frequent (99-80%)); Hypophosphatemic rickets (Obligate (100%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Childhood; Infancy

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 Autosomal recessive hypophosphatemic rickets is Orthopaedics, with a orthopaedic specialist 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.

• What explains the change in pain, movement or function?
• Which activities need adjustment while the diagnosis is being clarified?
• What are the roles of rehabilitation, observation and surgery in this situation?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Autosomal recessive hypophosphatemic rickets. 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.