Persistent fontanelles in Chihuahuas. Part I. Distribution and clinical relevance

Area of Science:

• Veterinary Neurology
• Comparative Anatomy
• Canine Genetics

Background:

• Chihuahuas frequently exhibit bregmatic fontanelles, often considered clinically insignificant.
• The prevalence and distribution of persistent fontanelles (PFs) in Chihuahuas are not well-documented.
• The association between PFs and Chiari-like malformation (CM) or syringomyelia (SM) in Chihuahuas remains unclear.

Purpose of the Study:

• To quantify and localize PFs in Chihuahuas.
• To compare PF occurrence in dogs with and without CM/SM-related clinical signs.
• To test the hypothesis that PFs are more prevalent and extensive in Chihuahuas with CM/SM.

Main Methods:

• Fifty client-owned Chihuahuas were evaluated.
• Dogs were assessed for the presence, number, and location of PFs.
• Comparison of PF characteristics between dogs with and without CM/SM clinical signs.

Main Results:

• 92% of Chihuahuas (46/50) had one or more PFs.
• A mean of 2.8 PFs were observed, located dorsally, caudally, and laterally.
• Dogs with CM/SM clinical signs had significantly more affected cranial sutures and larger total PF area.

Conclusions:

• Persistent fontanelles are highly prevalent in Chihuahuas, occurring across various cranial regions.
• The number and size of PFs are significantly greater in Chihuahuas exhibiting clinical signs of CM/SM.
• Findings suggest a potential link between PFs and CM/SM, warranting further investigation.