Morphological and Genetic Characterization of a Miniature Single Coat Prapso Shih Tzu: An Individual Case Study

This case study provides a morphological and genetic interpretation of a female miniature prapso Shih Tzu, a minority phenotype within the breed. The specimen exhibits a single-layer coat, absence of undercoat, reduced body size, and an intermediate craniofacial morphotype. These traits are examined in relation to current knowledge on coat architecture, skull-shape genetics, and size modulation in small domestic dogs. Findings indicate the expression of recessive allelic combinations linked to simplified coat structures and polygenic influences affecting facial shortening, nasal bridge development, and orbital configuration. Functional examination revealed efficient respiration without traits associated with extreme brachycephaly, while behavioural observations showed rapid learning and strong social responsiveness. This case exemplifies a naturally occurring intra-breed phenotype and highlights the importance of documenting morphological and genetic variants not captured in standardised breed descriptions.