Dog Diseases Database
Every hereditary and common canine condition — with tests, affected body regions, and the breeds where each shows up most.
Filters
- ModerateGeneral / metabolicAutosomal recessive
Methaemoglobinaemia, CYB5R3-related
This is an inherited blood disorder where a deficiency in a specific enzyme, cytochrome b5 reductase, impairs the red blood cells' ability to carry oxygen. Without this enzyme, an abnormal form of hemoglobin—the protein responsible for transporting oxygen—builds up in the bloodstream, reducing the amount of oxygen delivered to the body's tissues.
Tested via: DNA testView details - SevereEyesAutosomal recessive
Microphthalmia with haematopoietic defects, DNAJC21-related
This severe inherited disorder affects eye development and the blood-producing system in the bone marrow, caused by a genetic mutation in the DNAJC1 gene. Because the bone marrow cannot produce enough vital blood cells, affected dogs suffer from a lack of oxygen-carrying red blood cells (anemia) and a severely weakened immune system. This condition is genetically similar to bone marrow failure syndromes seen in humans.
Tested via: Eye exam, DNA testView details - HighEyesAutosomal recessive
Microphthalmia, isolated, with coloboma
This is a congenital developmental disorder of the eyes where the eyeball does not grow to its normal size, a condition known as microphthalmia. It is accompanied by coloboma, which refers to structural gaps or missing tissue in parts of the eye such as the iris or retina. Because these structures fail to fuse properly during embryonic development, the eye's ability to function is severely compromised.
Tested via: Eye examView details - MildEyesUnknown
Miosis
Miosis is an eye condition characterized by abnormally small, constricted pupils that do not dilate, or widen, properly. This occurs due to a dysfunction in the muscles of the iris or the nervous system pathways that control pupil movement. It can be congenital, meaning a puppy is born with it, and is routinely assessed during official veterinary eye examinations.
Tested via: Eye examView details - ModerateMouth & teethComplex
Mislocated polydontic maxillary incisor teeth
This is a congenital dental condition where extra, or supernumerary, front teeth (incisors) grow in the upper jaw in abnormal positions. This misalignment affects the mouth and dental structure, often causing crowding and improper contact between the upper and lower teeth. Over time, this crowding can lead to painful rubbing against the gums and surrounding soft tissues.
Tested via: Clinical examView details - SevereHead / nervous systemAutosomal recessive
Mitochondrial fission encephalopathy(MFE)
Mitochondrial fission encephalopathy, also known as MFF-related encephalopathy, is a severe inherited brain disorder where the normal division of mitochondria (the energy-producing parts of a cell) is impaired. Without this division, nerve cells in the brain suffer a severe energy deficit and progressively die. This condition is historically referred to as familial cerebellar ataxia with hydrocephalus.
Tested via: DNA testView details - HighHeartComplex
Mitral stenosis(MS)
Mitral stenosis is a congenital heart defect where the mitral valve, which controls blood flow between the left upper and lower chambers of the heart, is abnormally narrowed. This narrowing restricts normal blood flow through the heart, causing blood to back up into the blood vessels of the lungs. Over time, this fluid buildup puts significant strain on the cardiovascular system.
Tested via: Cardiac examView details - MildGeneral / metabolicX-linked
Modifier of copper toxicosis, ATP7A-related
This genetic variant in the ATP7A gene acts as a modifier for copper toxicosis, which is a metabolic disorder affecting the liver. It influences how copper is absorbed and stored in the body, potentially reducing the severity of copper accumulation in the liver. Because it is a modifier, it does not cause disease on its own but instead alters how another genetic condition behaves.
Tested via: DNA testView details - ModerateGeneral / metabolicComplex
Modifier of copper toxicosis, RETN-related
This genetic variant in the RETN gene acts as a modifier for copper toxicosis, a metabolic condition affecting the liver. It does not cause the disease on its own, but it influences how severely copper accumulates in the liver tissue. This accumulation can lead to progressive liver damage and inflammation.
Tested via: DNA testView details - SevereGeneral / metabolicX-linked
Mucopolysaccharidosis II(MPS II)
Mucopolysaccharidosis II (MPS II) is a severe, inherited metabolic disorder caused by a deficiency in an enzyme needed to break down complex sugar molecules. Without this enzyme, these sugars build up inside cells, causing progressive damage to multiple organ systems, including the skeleton and the nervous system. This condition is inherited in an X-linked manner, meaning it primarily affects male dogs.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Mucopolysaccharidosis IIIA(MPS IIIA)
Mucopolysaccharidosis IIIA is an inherited metabolic disorder where the body lacks a specific enzyme needed to break down complex sugar molecules. Without this enzyme, these sugars build up to toxic levels inside cells, causing progressive and irreversible damage to the central nervous system, particularly the brain.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Mucopolysaccharidosis IIIB(MPS IIIB)
Mucopolysaccharidosis IIIB is an inherited lysosomal storage disease that primarily affects the brain and nervous system. It is caused by a deficiency in a specific enzyme needed to break down complex sugar molecules. Without this enzyme, these sugars accumulate inside the body's cells, leading to progressive cellular damage.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Mucopolysaccharidosis VI(MPS VI)
Mucopolysaccharidosis VI (MPS VI) is an inherited metabolic disease where the body lacks a specific enzyme called arylsulfatase B. Without this enzyme, complex sugar molecules called glycosaminoglycans cannot be broken down and instead build up to harmful levels in the body's tissues. This accumulation primarily damages the skeletal system, joints, and eyes.
Tested via: DNA testView details - SevereGeneral / metabolicComplex
Multiple anomalies
This is an inherited condition, passed down on the X chromosome, that causes multiple structural malformations across several organ systems, such as the skeleton, heart, and nervous system. These developmental defects occur while the puppy is still growing in the womb, leading to complex physical abnormalities at birth.
View details - SevereGeneral / metabolicComplex
Multiple autoimmune diseases syndrome
This syndrome occurs when a dog's immune system mistakenly identifies its own healthy tissues as foreign threats and attacks multiple organs or systems at the same time or in sequence. Because it involves several distinct autoimmune diseases, it can affect various parts of the body simultaneously, including the skin, joints, and blood vessels. This widespread immune malfunction leads to chronic, systemic inflammation.
View details - MildGeneral / metabolicUnknown
Multiple Lipomatosis
Multiple lipomatosis is a benign skin condition where multiple non-cancerous fatty tumors, called lipomas, grow in the tissue just beneath the dog's skin. These lumps are made of normal fat cells that have multiplied abnormally, but they do not spread to other organs or cause cancer. It primarily affects the subcutaneous tissue, which is the deep layer of the skin.
View details - HighEyesAutosomal dominant
Multiple ocular defects(MOD)
Multiple ocular defects (MOD) is an inherited condition affecting the development of the eye's structures, such as the lens, retina, iris, or cornea. This abnormal development is caused by a genetic mutation that disrupts how these vital parts of the eye form. Because multiple components of the eye are malformed from birth, the condition typically results in severe vision loss or complete blindness.
Tested via: Eye examView details - HighEyesAutosomal recessive
Multiple ocular defects, COL11A1-related
This genetic condition affects the development of the eyes due to a mutation in the COL11A1 gene, which is responsible for producing a specific type of collagen. Collagen is a crucial structural protein that helps maintain the shape and stability of various tissues inside the eye. Without properly functioning collagen, multiple parts of the eye fail to develop correctly, leading to severe structural defects.
Tested via: Eye exam, DNA testView details - SevereHead / nervous systemAutosomal recessive
Multiple System Degeneration (Chinese Crested)(CMSD)
Multiple System Degeneration, also known as Progressive Neuronal Abiotrophy (PNA), is an inherited neurological disease where specific areas of the brain, particularly the cerebellum, prematurely waste away. The cerebellum is the control center responsible for coordinating voluntary movements and balance. As these brain cells degenerate, the dog gradually loses the ability to control its motor functions.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Muscle hypertrophy, dysphagia, and gait abnormalities
This is an inherited muscle disorder, or myopathy, that affects the skeletal muscles responsible for movement and swallowing. It is caused by genetic mutations that disrupt normal muscle cell structure, leading to abnormal muscle enlargement and a loss of normal function.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Muscular Dystrophy 2(MD)
Muscular Dystrophy 2 is an inherited genetic disorder that affects the skeletal muscles, specifically covering the subtypes LGMDR3 and LGMDR6. It is caused by a deficiency in essential structural proteins that normally protect muscle fibers from damage during movement. Without these proteins, the muscle cells gradually break down and degenerate over time.
Tested via: DNA testView details - SevereGeneral / metabolicAutosomal recessive
Muscular dystrophy-dystroglycanopathy, LARGE1-related(MDD)
This is an inherited muscle disorder where a genetic defect in the LARGE1 gene disrupts the stability of muscle cell membranes. Without this protective support, the skeletal muscles undergo progressive and irreversible breakdown. This leads to a gradual loss of muscle function throughout the body.
Tested via: DNA testView details - SevereGeneral / metabolicUnknown
Muscular dystrophy, dysphagia-associated
This is a genetic muscle disorder that causes the progressive breakdown of skeletal muscles, particularly affecting the muscles in the throat and esophagus used for swallowing. The loss of muscle function in these areas makes it difficult for the dog to move food safely into the stomach.
View details - SevereGeneral / metabolicAutosomal recessive
Muscular dystrophy, Ullrich type, COL6A3-related(UCMD)
This is an inherited muscle disorder caused by a genetic defect in collagen VI, which is a structural protein essential for holding muscle cells together. Without this properly functioning protein, the muscle tissue becomes unstable and progressively wastes away. This primarily damages the musculoskeletal system, leading to permanent muscle loss.
Tested via: DNA testView details - SevereGeneral / metabolicUnknown
Mycosis fungoides(MF)
Mycosis fungoides is a rare, malignant type of skin cancer known as a cutaneous T-cell lymphoma. In this condition, abnormal white blood cells, which normally help the body fight infection, mistakenly accumulate in the skin layers. This buildup disrupts the normal structure of the skin and leads to progressive tissue damage.
View details
Frequently asked questions
What is the HonestDog dog diseases database?
Our database brings together hereditary and common canine conditions with symptoms, inheritance patterns, testing methods, and the breeds where each matters most.
How do I find the right test for a condition?
Search by disease name, abbreviation or symptom, then filter by test type, body region or severity. Each detail page lists recommended tests and affected breeds.
Why do health tests matter for breeders?
Health tests help catch hereditary conditions early and support responsible breeding. Many breed clubs require or recommend specific tests as part of their screening.
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