A Rare Genetic Intersection: Down Syndrome With Coexisting Spinal Muscular Atrophy

Area of Science:

• Genetics
• Pediatrics
• Neurology

Background:

• Down syndrome (DS) is a chromosomal disorder, while spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder.
• The co-occurrence of DS and SMA is exceptionally rare, presenting unique clinical and diagnostic challenges.

Observation:

• A three-month-old infant presented with respiratory failure, initially diagnosed with DS based on clinical features and chromosomal analysis.
• Recurrent infections and extubation difficulties prompted further investigation, revealing a homozygous pathogenic mutation for SMA type 1 via whole exome sequencing.

Findings:

• The case demonstrates the diagnostic complexity arising from overlapping symptoms like hypotonia and motor delays in both DS and SMA.
• Whole exome sequencing was critical in identifying the co-existing SMA diagnosis.

Implications:

• This report emphasizes the need for comprehensive genetic evaluation in infants with syndromic features and overlapping symptoms.
• Clinicians require heightened awareness for rare co-occurring genetic conditions to ensure appropriate management, counseling, and improved patient outcomes.