Congenital
Present at birth, whether caused by genetic factors, developmental abnormalities during gestation, or environmental influences on the developing embryo. Congenital conditions may be immediately apparent or may not manifest clinically until later in life.
Congenital means “present at birth.” It describes any condition that exists from the time of birth, regardless of whether it was caused by genetic inheritance, developmental errors during gestation, maternal infections, toxin exposure during pregnancy, or nutritional deficiencies affecting the developing embryo.
Congenital vs Hereditary
These terms are related but not synonymous:
- Congenital: present at birth (descriptive of timing)
- Hereditary/genetic: caused by inherited genetic factors (descriptive of cause)
A condition can be congenital but not hereditary (e.g., birth defect from maternal infection). It can also be hereditary but not clinically congenital — meaning the genetic predisposition is present from birth but the clinical disease does not manifest until later in life (e.g., progressive retinal atrophy, which is genetically present from birth but typically causes vision loss in adulthood).
Common Congenital Conditions in Dogs
Cardiovascular
- Congenital heart defects: patent ductus arteriosus (PDA), pulmonic stenosis, subaortic stenosis, ventricular septal defect. These are structural heart abnormalities present from birth.
- Portosystemic shunt: abnormal blood vessel bypassing the liver, preventing normal detoxification.
Skeletal
- Hip dysplasia: genetic predisposition is present at birth, though clinical signs typically develop during growth or in adulthood.
- Atlantoaxial instability: congenital malformation of the first two cervical vertebrae, most common in toy breeds.
Neurologic
- Congenital hydrocephalus: excessive cerebrospinal fluid in the brain ventricles, common in certain toy and brachycephalic breeds.
- Congenital deafness: present from birth, associated with white coat color genetics in certain breeds.
Other
- Cleft palate: failure of palatal fusion during development
- Cryptorchidism: failure of one or both testicles to descend into the scrotum
Screening Implications
Understanding congenital conditions is essential for breeding programs. Genetic testing (DNA panel testing) can identify carriers of hereditary congenital conditions before breeding. Neonatal and puppy examinations can detect structural congenital defects early, when intervention options are broadest.