HDR Syndrome (Hypoparathyroidism, Deafness, Renal Dysplasia)

What is HDR Syndrome (Hypoparathyroidism, Deafness, Renal Dysplasia)?

HDR syndrome is a rare genetic condition that affects three main body systems. The name describes its three key features. Hypoparathyroidism means your parathyroid glands do not make enough parathyroid hormone. Deafness refers to hearing loss that is usually present from birth. Renal dysplasia means the kidneys did not develop normally before birth.

This condition is caused by mutations in the GATA3 gene. This gene provides instructions for making a protein that helps develop parathyroid glands, the inner ear, and kidneys. When the gene does not work properly, these organs do not form or function correctly. HDR syndrome is inherited in an autosomal dominant pattern. This means one copy of the changed gene in each cell is enough to cause the disorder.

The severity of symptoms varies widely from person to person, even within the same family. Some people have all three features, while others may have only one or two. Early diagnosis helps manage calcium levels and prevent complications from low calcium in the blood.

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Symptoms

Low blood calcium levels causing muscle cramps, tingling in hands and feet, or seizures
Hearing loss ranging from mild to profound, usually present from birth
Kidney problems that may range from mild abnormalities to severe kidney disease
Muscle spasms or twitching, particularly around the mouth or in the hands
Abnormal heart rhythms due to low calcium
Fatigue and weakness
Dry skin and brittle nails
Dental problems including weak tooth enamel

Some people with HDR syndrome have mild symptoms that go unnoticed for years. Others may be diagnosed in infancy due to severe low calcium or kidney problems. The hearing loss is typically the first symptom recognized, often during newborn hearing screening.

Causes and risk factors

HDR syndrome is caused by mutations in the GATA3 gene. This gene is essential for the normal development of parathyroid glands, the inner ear structures responsible for hearing, and the kidneys. When GATA3 does not function properly, these organs fail to develop or work correctly. The condition is inherited in an autosomal dominant pattern, meaning a child needs only one mutated copy of the gene from one parent to develop the syndrome. However, about half of cases result from new mutations with no family history.

There are no known environmental or lifestyle risk factors that cause HDR syndrome. It is purely genetic. Family history is the primary risk factor. If one parent has HDR syndrome, each child has a 50 percent chance of inheriting the condition. Genetic counseling can help families understand their risks and make informed decisions about testing and family planning.

How it's diagnosed

Diagnosis begins with recognizing the pattern of symptoms, including low calcium, hearing loss, and kidney abnormalities. Blood tests measure parathyroid hormone levels and calcium. People with HDR syndrome typically have low PTH levels along with low calcium, which is unusual because PTH normally rises when calcium is low. Rite Aid offers parathyroid hormone testing as an add-on to help monitor this condition once diagnosed. Kidney function tests and imaging studies check for renal problems.

Genetic testing confirms the diagnosis by identifying GATA3 gene mutations. Hearing tests assess the type and severity of hearing loss. A complete evaluation usually involves endocrinologists, nephrologists, and geneticists working together. Early diagnosis is important because managing calcium levels prevents serious complications like seizures and heart rhythm problems.

Treatment options

Calcium supplements to maintain normal blood calcium levels
Active vitamin D supplements, such as calcitriol, to help the body absorb calcium
Regular blood tests to monitor calcium, phosphate, and kidney function
Hearing aids or cochlear implants for hearing loss
Kidney monitoring and treatment if renal function declines
High-calcium diet including dairy, leafy greens, and fortified foods
Avoiding medications that lower calcium levels
Regular cardiology checkups to monitor heart rhythm
Genetic counseling for family planning

Frequently asked questions

HDR syndrome is a rare genetic condition affecting parathyroid glands, hearing, and kidney development. It is caused by mutations in the GATA3 gene. The three main features are low parathyroid hormone levels, hearing loss, and abnormal kidney development. Symptoms vary widely in severity among affected individuals.

HDR syndrome follows an autosomal dominant inheritance pattern. This means one mutated copy of the GATA3 gene is enough to cause the condition. If one parent has HDR syndrome, each child has a 50 percent chance of inheriting it. About half of cases occur from new mutations with no family history.

The three main features are hypoparathyroidism, deafness, and kidney abnormalities. Low parathyroid hormone causes low calcium, leading to muscle cramps, tingling, and potentially seizures. Hearing loss ranges from mild to profound and is usually present from birth. Kidney problems vary from mild abnormalities to serious kidney disease.

Blood tests help identify HDR syndrome by measuring parathyroid hormone and calcium levels. People with this condition typically have low PTH and low calcium together. Genetic testing of the GATA3 gene confirms the diagnosis. Blood tests also monitor kidney function and electrolyte balance.

Treatment involves calcium supplements and active vitamin D to maintain normal blood calcium levels. Regular blood tests monitor calcium, phosphate, and kidney function. A diet rich in calcium from dairy, leafy greens, and fortified foods helps. Proper management prevents complications like seizures and abnormal heart rhythms.

The hearing loss itself is permanent, but it can be managed with hearing aids or cochlear implants. The severity ranges from mild to profound. Early hearing intervention helps with speech and language development in children. Regular hearing assessments track any changes over time.

Kidney abnormalities range from mild structural differences to severe dysplasia affecting kidney function. Some people develop chronic kidney disease requiring ongoing monitoring. Regular urine and blood tests check kidney function. Treatment depends on severity and may include medications or dietary changes to protect remaining kidney function.

Many people with HDR syndrome live relatively normal lives with proper management. Regular monitoring and treatment of calcium levels prevent serious complications. Hearing aids or cochlear implants help with communication. The main challenges are managing low calcium and monitoring kidney health throughout life.

Testing frequency depends on symptom severity and stability. Most people need blood tests every few months to monitor calcium, phosphate, PTH, and kidney function. Annual hearing tests and kidney imaging may be recommended. Your doctor will create a personalized monitoring schedule based on your specific needs.

Yes, family members should consider genetic counseling and testing. Because HDR syndrome is autosomal dominant, children and siblings of affected individuals may carry the mutation. Early diagnosis allows for proactive management of calcium levels and monitoring of hearing and kidney function. Genetic testing identifies at-risk family members before symptoms develop.