Written in the Genes

While these inherited disorders are seen in all cats, pedigree breeds are more prone due to selective breeding. Understanding the causes, diagnosis, and treatment of feline genetic diseases is crucial to ensuring your cat leads a healthy and happy life.

Paws, genes, and inherited scenes

Recent advances in genetic testing have helped identify gene defects behind many inherited conditions in cats. Some diseases are caused by a single gene and are easier to diagnose, while others involve multiple genes or a mix of genetic and environmental factors. Genetic disorders can vary by region, but global travel means many are now seen worldwide. Veterinary labs now offer DNA tests for inherited diseases, coat colors, and cat parentage.

When DNA testing cats for breeding purposes, a veterinarian should supervise the process, and a trusted lab should be used. International Cat Care recommends linking test results to a permanent ID, like a microchip, and ensuring a vet collects the sample to verify and record the cat’s identity.

Types of Feline Genetic Diseases

Here are some of the most common genetic diseases in cats.

Polycystic Kidney Disease

Polycystic kidney disease (PKD) is an inherited disorder that can lead to feline kidney failure. In this disease, small fluid-filled cysts are formed in the feline kidneys. PKD is a common inherited kidney disease in cats, especially in Persian and related breeds.

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats, where the heart muscle thickens and pumps less blood. It can cause a fast or irregular heartbeat, and some breeds like Maine Coons and Ragdolls are more likely to have it due to genetic mutations. A DNA test is available for these breeds.

Diabetes Mellitus

Diabetes mellitus in cats is a condition where blood sugar stays too high because the body lacks insulin or doesn’t respond to it properly. While treatable, it can lead to cells being starved of energy. It’s more common in random-bred cats, but some breeds like Burmese, Siamese, and Russian Blues may have a higher risk.

Feline Lower Urinary Tract Disease (FLUTD)

Feline Lower Urinary Tract Disease (FLUTD) refers to various conditions affecting a cat’s bladder and urethra, such as cystitis, urinary stones, and blockages. It affects about 1–2% of cats, with Persians at higher risk and Siamese at lower risk.

Progressive Retinal Atrophy

Progressive Retinal Atrophy (PRA) is an inherited eye disease that causes blindness later in life, mainly in Abyssinians, Somali’s, and Ocicats. It’s caused by recessive genes, and while untreatable, blind cats can still live fulfilling lives.

Deafness

Deafness is common in white cats, especially those with blue eyes, due to the dominant W gene, which affects both coat color and inner ear development, increasing the risk of hearing loss.

Glycogen Storage Disease (GSD)

This group of inherited disorders primarily affects Norwegian Forest Cats. GSD hampers the cat’s ability to break down and utilize glycogen, stored energy. Affected cats may show muscle weakness, exercise intolerance, and tremors. As the disease advances, it could lead to severe heart and liver conditions, reducing the cat’s lifespan.

Mucopolysaccharidosis (MPS)

Mucopolysaccharidosis (MPS) is a genetic disorder seen mostly in Siamese and related breeds, caused by a lack of enzymes needed to break down certain molecules. This buildup leads to issues like facial deformities, vision problems, stunted growth, and a shorter lifespan.

Spinal Muscular Atrophy (SMA)

Spinal Muscular Atrophy (SMA) is a genetic condition in Maine Coon cats that causes muscle weakness, especially in the back legs, due to nerve damage. While their movement may be affected, cats with SMA can live a full, happy life with proper care.

Causes of Feline Genetic Diseases

The common reasons why certain breeds of cats have genetic diseases include –

• Inheritance of abnormal genes
• Mutations
• Environmental triggers
• Exposure to risk factors

Epigenetics (Epigenetics is the study of how a cat’s environment or experiences can affect how its genes work, without changing the DNA itself. These changes can sometimes lead to diseases, like FLUTD, in breeds such as Persians).

Breeding practices – inbreeding and selective breeding

Meow-lecular Medicine – Diagnostic Tests

Physical Examination

Diagnosing genetic conditions in cats typically begins with an exhaustive physical evaluation. By assessing the cat’s physical condition and behavioral patterns, veterinarians may identify symptoms indicative of certain inherited diseases, especially if it’s a pedigree cat.

Genetic Testing

DNA testing is the most reliable way to detect genetic diseases in cats. By analyzing a sample from blood or tissue, labs can identify conditions like PKD, HCM, and GSD, helping confirm diagnoses, check carrier status, or predict future risk.

Biopsy

Occasionally, performing a biopsy may be necessary to diagnose a genetic condition. This procedure involves extracting a small tissue sample from the impacted organ or body part. This sample is then microscopically examined for abnormal cells or structures. Biopsies prove particularly beneficial when diagnosing genetic diseases that trigger tumors or skin afflictions.

Blood Tests and Other Laboratory Tests

Blood tests help detect inherited diseases by revealing irregularities in blood cells or chemistry, while also identifying the cat’s blood type. Additional tests, like urine and fecal analysis, provide a fuller picture of the cat’s overall health and organ function.

Medical History

A detailed health history helps diagnose inherited diseases in cats. Vets look at the cat’s past illnesses and treatments, as well as the health of its parents and siblings, to assess the risk of genetic conditions.

Imaging Tests

Imaging tests, such as X-rays, ultrasounds, and CT scans, are commonly employed to diagnose genetic diseases that impact the cat’s physical structures. For instance, X-rays can highlight skeletal defects, whereas ultrasounds can uncover issues with organs like the heart or kidneys. These tests can often pinpoint physical indicators of a disease even before the cat starts showing symptoms, and are identified in cats across the feline population.

Electrodiagnostic Testing

Electrodiagnostic tests like ECG and EMG check the electrical activity of the heart, nerves, or muscles to detect genetic disorders. For example, an ECG can help diagnose heart conditions like Hypertrophic Cardiomyopathy (HCM).

Unraveling the DNA Knot: Treatment Paths for Genetic Cat Ailments

The treatment options for genetic diseases in cats largely depend on the specific disease. However, most treatments aim to manage symptoms, slow the progression of the disease, and improve the cat’s quality of life. Let’s look at some general categories of treatment options –

Tailored Care with Medications

Cats with heart conditions like HCM may be treated with ACE inhibitors, beta-blockers, and anticoagulants to reduce heart strain, control heart rate, and prevent clots. For PKD, treatments may include blood pressure medications, phosphate binders, calcium supplements, and drugs to manage anemia.

Dietary Management

Kidney-friendly diet is for cats with PKD. It is typically low in phosphorus and protein to reduce the kidneys’ workload. It also usually contains increased levels of B vitamins and antioxidants to help the body deal with the toxins that the kidneys can’t filter out as effectively.

A diet for cats with diabetes usually involves high protein and low carbohydrate content to minimize blood sugar spikes after meals. Consistent feeding schedules and portion control are essential to managing feline diabetes.

Regular Monitoring and Check-ups

Regular vet visits allow for ongoing evaluation of the cat’s health and adjustments to the treatment plan as necessary. This could include –

• Blood Tests
• Ultrasound or X-rays
• Genetic Counseling
• DNA Testing
• Physical Therapy -stretching and massage, hydrotherapy, supportive care

Sensory Enrichment

For cats with progressive conditions like Progressive Retinal Atrophy (PRA), toys that stimulate other senses, like sound or smell, can keep a cat engaged and happy.

Safe Environment

For cats with PRA, removing potential hazards, keeping furniture in the same place, and using night lights can help them navigate their environment safely.

Remember that not all cat health issues, including irritation caused by various factors, are preventable. As a pet parent, offering your feline friend a secure, caring environment and high-quality veterinary care is the best you can do!

(Dr. Deesha Gupta – Ph.D Scholar, Animal Genetics and Breeding, Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu)