Spondylometaphyseal dysplasia-cone-rod dystrophy syndrome

What it is

From: Orphanet

Spondylometaphyseal dysplasia-cone-rod dystrophy syndrome is characterised by the association of spondylometaphyseal dysplasia (marked by platyspondyly, shortening of the tubular bones and progressive metaphyseal irregularity and cupping), with postnatal growth retardation and progressive visual impairment due to cone-rod dystrophy. So far, it has been described in eight individuals. Transmission appears to be autosomal recessive.

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.

Abnormality of epiphysis morphology · Very frequent (99-80%)

An anomaly of epiphysis, which is the expanded articular end of a long bone that developes from a secondary ossification center, and which during the period of growth is either entirely cartilaginous or is separated from the shaft by a cartilaginous disk.

Abnormality of retinal pigmentation · Very frequent (99-80%)

Any deviation from the normal pigmentation of the retina.

Bowing of the legs · Very frequent (99-80%)

A bending or abnormal curvature affecting a long bone of the leg.

Bowing of the long bones · Very frequent (99-80%)

A bending or abnormal curvature of a long bone.

Brachydactyly · Very frequent (99-80%)

Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.

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.

Flared metaphysis · Very frequent (99-80%)

The presence of a splayed (i.e.,flared) metaphyseal segment of one or more long bones.

Ivory epiphyses · Very frequent (99-80%)

Sclerosis of the epiphyses, leading to an increased degree of radiopacity (white or ivory appearance) in X-rays.

Metaphyseal irregularity · Very frequent (99-80%)

Irregularity of the normally smooth surface of the metaphyses.

Metaphyseal spurs · Very frequent (99-80%)

Bony outgrowths that extend laterally from the margin of the metaphysis.

Ovoid vertebral bodies · Very frequent (99-80%)

When viewed in lateral radiographs, vertebral bodies have a roughly rectangular configuration. This term applies if the vertebral body appears rounded or oval.

Platyspondyly · Very frequent (99-80%)

A flattened vertebral body shape with reduced distance between the vertebral endplates.

Retinal thinning · Very frequent (99-80%)

Reduced anteroposterior thickness of the retina. This phenotype can be appreciated by retinal optical coherence tomography (OCT).

Rhizomelia · Very frequent (99-80%)

Disproportionate shortening of the proximal segment of limbs (i.e. the femur and humerus).

Other findings in the same source

From: Orphanet

Additional reported features include Severe short stature (Very frequent (99-80%)); Short long bone (Very frequent (99-80%)); Short metacarpal (Very frequent (99-80%)); Short phalanx of finger (Very frequent (99-80%)); Visual impairment (Very frequent (99-80%)); Cone/cone-rod dystrophy (Very frequent (99-80%)); Abnormality of refraction (Frequent (79-30%)); Cupped ribs (Frequent (79-30%)); Femoral spur (Frequent (79-30%)); Hypoplastic ilia (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

No data available

Inheritance in the source

From: Orphanet

Autosomal recessive

Frequency and the population described

From: Orphanet

Reported case(s): 18.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

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 Spondylometaphyseal dysplasia-cone-rod dystrophy syndrome 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 Spondylometaphyseal dysplasia-cone-rod dystrophy syndrome. 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.