Congenital muscular dystrophy without intellectual disability

What it is

From: Orphanet

A rare, genetic, congenital muscular dystrophy due to dystroglycanopathy characterized by a wide phenotypic spectrum which includes hypotonia and muscular weakness present at birth or early infancy, delayed or arrested motor development, and normal intellectual abilities with normal (or only mild abnormalities) neuroimaging studies. Feeding difficulties, joint and spinal deformities, and respiratory insufficiency may be associated. Decreased alpha-dystroglycan on immunohistochemical muscle staining and elevated serum creatine kinase are observed.

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.

Muscular dystrophy · Very frequent (99-80%)

The term dystrophy means abnormal growth. However, muscular dystrophy is used to describe primary myopathies with a genetic basis and a progressive course characterized by progressive skeletal muscle weakness and wasting, defects in muscle proteins, and histological features of muscle fiber degeneration (necrosis) and regeneration. If possible, it is preferred to use other HPO terms to describe the precise phenotypic abnormalities.

Abnormal cerebral white matter morphology · Frequent (79-30%)

An abnormality of the cerebral white matter.

Achilles tendon contracture · Frequent (79-30%)

A contracture of the Achilles tendon.

Cerebellar atrophy · Frequent (79-30%)

Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.

EMG: myopathic abnormalities · Frequent (79-30%)

The presence of abnormal electromyographic patterns indicative of myopathy, such as small-short polyphasic motor unit potentials.

Facial diplegia · Frequent (79-30%)

Facial diplegia refers to bilateral facial palsy (bilateral facial palsy is much rarer than unilateral facial palsy).

Fatty replacement of skeletal muscle · Frequent (79-30%)

Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers

Gait disturbance · Frequent (79-30%)

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

Generalized hypotonia · Frequent (79-30%)

Generalized muscular hypotonia (abnormally low muscle tone).

Generalized muscle weakness · Frequent (79-30%)

Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature.

Limb-girdle muscle atrophy · Frequent (79-30%)

Muscular atrophy affecting the muscles of the limb girdle.

Motor delay · Frequent (79-30%)

A type of Developmental delay characterized by a delay in acquiring motor skills.

Muscle spasm · Frequent (79-30%)

Sudden and involuntary contractions of one or more muscles.

Myalgia · Frequent (79-30%)

Pain in muscle.

Other findings in the same source

From: Orphanet

Additional reported features include Neonatal hypotonia (Frequent (79-30%)); Proximal amyotrophy (Frequent (79-30%)); Reduced muscle fiber alpha dystroglycan (Frequent (79-30%)); Tip-toe gait (Frequent (79-30%)); Frequent falls (Frequent (79-30%)); Mildly elevated creatine kinase (Frequent (79-30%)); Kyphoscoliosis (Occasional (29-5%)); Microcephaly (Occasional (29-5%)); Cerebellar cyst (Occasional (29-5%)); Gray matter heterotopia (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Infancy; Neonatal

Inheritance in the source

From: Orphanet

Autosomal recessive

Frequency and the population described

From: Orphanet

Point prevalence: Unknown; Worldwide; Class only. Annual incidence: Unknown; 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 Congenital muscular dystrophy without intellectual disability is Neurology, with a neurologist 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 nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Congenital muscular dystrophy without intellectual disability. 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.