Schwartz-Jampel syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Schwartz-Jampel syndrome is a rare condition characterized by permanent muscle stiffness (myotonia) and bone abnormalities known as chondrodysplasia. The signs and symptoms of this condition become apparent sometime after birth, usually in early childhood. Either muscle stiffness or chondrodysplasia can appear first. The muscle and bone abnormalities worsen in childhood, although most affected individuals have a normal lifespan. The specific features of Schwartz-Jampel syndrome vary widely.

Myotonia involves continuous tensing (contraction) of muscles used for movement (skeletal muscles) throughout the body. This sustained muscle contraction causes stiffness that interferes with eating, sitting, walking, and other movements. Sustained contraction of muscles in the face leads to a fixed, "mask-like" facial expression with narrow eye openings (blepharophimosis) and pursed lips. This facial appearance is very specific to Schwartz-Jampel syndrome. Affected individuals may also be nearsighted and experience abnormal blinking or spasms of the eyelids (blepharospasm).

Chondrodysplasia affects the development of the skeleton, particularly the long bones in the arms and legs and the bones of the hips. These bones are shortened and unusually wide at the ends, so affected individuals have short stature. The long bones may also be abnormally curved (bowed). Other bone abnormalities associated with Schwartz-Jampel syndrome include a protruding chest (pectus carinatum), abnormal curvature of the spine, flattened bones of the spine (platyspondyly), and joint abnormalities called contractures that further restrict movement.

Researchers originally described two types of Schwartz-Jampel syndrome. Type 1 has the signs and symptoms described above, while type 2 has more severe bone abnormalities and other health problems and is usually life-threatening in early infancy. Researchers have since discovered that the condition they thought was Schwartz-Jampel syndrome type 2 is actually part of another disorder, Stüve-Wiedemann syndrome, which is caused by mutations in a different gene. They have recommended that the designation Schwartz-Jampel syndrome type 2 no longer be used.

ORPHANET DEFINITION A rare, genetic neuromuscular disease characterized by permanent myotonia, mask-like facies (with blepharospasm, narrow palpebral fissures, small mouth with pursed lips and puckered chin) , and chondrodysplasia (variably manifesting with short stature, pectus carinatum, kyphoscoliosis, bowing of long bones, epiphyseal, metaphyseal, and hip dysplasia).

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Autosomal recessive

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 129.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

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 metaphysis morphology · Very frequent (99-80%)

An abnormality of one or more metaphysis, i.e., of the somewhat wider portion of a long bone that is adjacent to the epiphyseal growth plate and grows during childhood.

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.

Arthrogryposis multiplex congenita · Very frequent (99-80%)

Multiple congenital contractures in different body areas.

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

A bending or abnormal curvature of a long bone.

EMG abnormality · Very frequent (99-80%)

Abnormal results of investigations using electromyography (EMG).

Elevated circulating aldolase concentration · Very frequent (99-80%)

Concentration of fructose 1,6-bisphosphate aldolase in the blood circulation above the upper limit of normal.

Elevated circulating creatine kinase concentration · Very frequent (99-80%)

The activity of creatine kinase in the blood circulation is above the upper limit of normal.

Everted lower lip vermilion · Very frequent (99-80%)

An abnormal configuration of the lower lip such that it is turned outward i.e., everted, with the Inner aspect of the lower lip vermilion (normally opposing the teeth) being visible in a frontal view.

Full cheeks · Very frequent (99-80%)

Increased prominence or roundness of soft tissues between zygomata and mandible.

Gait disturbance · Very frequent (99-80%)

The term gait disturbance can refer to any disruption of the ability to walk.

Genu valgum · Very frequent (99-80%)

The legs angle inward, such that the knees are close together and the ankles far apart.

Hip dysplasia · Very frequent (99-80%)

The presence of developmental dysplasia of the hip.

Hypertonia · Very frequent (99-80%)

A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.

Intellectual disability · Very frequent (99-80%)

The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence.

Other findings in the same source

From: Orphanet

Additional reported features include Joint stiffness (Very frequent (99-80%)); Metatarsus valgus (Very frequent (99-80%)); Micromelia (Very frequent (99-80%)); Myotonia (Very frequent (99-80%)); Narrow mouth (Very frequent (99-80%)); Pes planus (Very frequent (99-80%)); Posteriorly rotated ears (Very frequent (99-80%)); Pursed lips (Very frequent (99-80%)); Short stature (Very frequent (99-80%)); Skeletal dysplasia (Very frequent (99-80%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Infancy; Neonatal

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal recessive

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 129.0; 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 Schwartz-Jampel 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 Schwartz-Jampel 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.