Diagnostic Criteria

While suggestive diagnostic criteria were proposed by as part of inclusion criteria for a research study on this condition, no consensus clinical diagnostic criteria for X-linked infantile spinal muscular atrophy have been published.

Suggestive Findings

X-linked infantile spinal muscular atrophy should be suspected in an individual with the following clinical, imaging, electrophysiologic, supportive laboratory, and family history findings.

Clinical features

• Congenital hypotonia and areflexia on physical examination

• Congenital contractures and/or fractures

• Digital contractures at birth. These usually remain throughout the individual's life.

Source: GeneReviews — "Spinal Muscular Atrophy, X-Linked Infantile"

Differential Diagnosis

The differential diagnosis of X-linked infantile spinal muscular atrophy (XL-SMA) caused by mutation of UBA1 includes other disorders associated with spinal muscular atrophy and/or arthrogryposis . Table 2. Disorders with Spinal Muscular Atrophy and/or Contractures in the Differential Diagnosis of X-Linked Infantile Spinal Muscular Atrophy

Management Guidelines

Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with X-linked infantile spinal muscular atrophy (XL-SMA), the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. Recommended Evaluations Following Initial Diagnosis in Individuals with X-Linked Infantile Spinal Muscular Atrophy

Source: GeneReviews — "Spinal Muscular Atrophy, X-Linked Infantile"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "Spinal Muscular Atrophy, X-Linked Infantile"

Surveillance Guidelines

Individuals with XL-SMA should be followed regularly by a physician familiar with this condition (e.g., a clinical geneticist). Other subspecialists involved in ongoing care include a neurologist, pulmonologist, orthopedist, physical and occupational therapists, nutritionist, and gastroenterologist as needed. Affected children should be followed at least monthly until the severity and disease course are more clearly delineated. Affected children frequently die in infancy or early childhood; their clinical status should be followed closely to optimize management, and to assure that the family has a good understanding of the progression and can make informed decisions.

Table 5.

Recommended Surveillance for Individuals with X-Linked Infantile Spinal Muscular Atrophy

System | Evaluation | Frequency

Growth

| Measurement of growth parameters | At each visit

Neurologic

| Neurologic assessment

Nutrition/

Feeding

| Monitor for symptoms of swallowing dysfunction, incl coughing, choking, /or recurrent pneumonia.

Respiratory1

| Assessment of respiratory status

Skeletal

| Assessment for kyphosis and/or scoliosis

1. Referral to a pulmonologist is recommended.

Source: GeneReviews — "Spinal Muscular Atrophy, X-Linked Infantile"