ICD-10: E72.51

Non-ketotic hyperglycinemia (NKH), classified under ICD-10-CM code E72.51, is a rare metabolic disorder characterized by an accumulation of glycine in the body, primarily affecting the central nervous system. This condition is also known as glycine encephalopathy due to its significant neurological implications.

Clinical Description

Pathophysiology

Non-ketotic hyperglycinemia results from a deficiency in the enzyme responsible for breaking down glycine, specifically the glycine cleavage system. This enzymatic defect leads to elevated levels of glycine in the blood and cerebrospinal fluid, which can disrupt normal brain function and lead to various neurological symptoms[4][5].

Symptoms

The clinical presentation of NKH can vary widely, but common symptoms include:

• Neurological Impairments: Infants may exhibit hypotonia (decreased muscle tone), lethargy, and seizures. As the condition progresses, developmental delays and intellectual disabilities may become apparent.
• Respiratory Issues: Some patients may experience respiratory distress due to central nervous system involvement.
• Coma: In severe cases, affected individuals may enter a comatose state, particularly during acute episodes[4][6].

Diagnosis

Diagnosis of non-ketotic hyperglycinemia typically involves:

• Clinical Evaluation: A thorough assessment of symptoms and family history.
• Biochemical Testing: Measurement of glycine levels in blood and cerebrospinal fluid, which are significantly elevated in NKH.
• Genetic Testing: Identification of mutations in the genes associated with the glycine cleavage system can confirm the diagnosis[5][6].

Management and Treatment

Currently, there is no definitive cure for non-ketotic hyperglycinemia. Management strategies focus on alleviating symptoms and preventing complications:

• Dietary Management: A low-protein diet may help reduce glycine levels, as glycine is an amino acid found in protein-rich foods.
• Medications: Some treatments may include the use of medications such as sodium benzoate or glycine antagonists, which aim to lower glycine levels or mitigate its effects on the brain[4][5].
• Supportive Care: Early intervention with physical therapy, occupational therapy, and educational support can help improve outcomes for affected individuals.

Prognosis

The prognosis for individuals with non-ketotic hyperglycinemia varies significantly. While some may experience severe neurological impairment, others may have milder symptoms and better developmental outcomes. Early diagnosis and intervention are crucial for improving quality of life and functional abilities[5][6].

In summary, non-ketotic hyperglycinemia (ICD-10 code E72.51) is a serious metabolic disorder that requires comprehensive management strategies to address its complex neurological effects. Ongoing research into treatment options and genetic counseling for affected families remains essential for improving patient outcomes.

Non-ketotic hyperglycinemia (NKH), associated with the ICD-10-CM code E72.51, is a rare metabolic disorder characterized by an accumulation of glycine in the body due to a deficiency in the enzyme responsible for its degradation. This condition primarily affects the central nervous system and can lead to a variety of clinical presentations, signs, and symptoms.

Clinical Presentation

Age of Onset

Non-ketotic hyperglycinemia typically presents in neonates or infants, although milder forms may be identified later in childhood or even adulthood. The severity of symptoms often correlates with the age of onset, with earlier presentations generally associated with more severe outcomes[1].

Neurological Symptoms

The most prominent clinical features of NKH are neurological in nature, including:

• Hypotonia: Decreased muscle tone is often one of the first signs observed in affected infants, leading to difficulties in movement and feeding[1].
• Seizures: Many patients experience seizures, which can be myoclonic, tonic-clonic, or focal. These seizures may be resistant to standard anticonvulsant therapies[1][2].
• Altered Consciousness: Patients may exhibit varying levels of consciousness, ranging from lethargy to coma, particularly during acute episodes[2].
• Developmental Delays: Children with NKH often show significant developmental delays, particularly in motor skills and cognitive function, as they grow older[1].

Behavioral and Psychiatric Symptoms

In older children and adults, behavioral issues such as irritability, hyperactivity, and psychiatric symptoms may emerge, reflecting the ongoing impact of glycine accumulation on brain function[2].

Signs

Physical Examination Findings

During a physical examination, clinicians may note:

• Abnormal Reflexes: Hyperreflexia or other abnormal reflex responses may be present due to central nervous system involvement[1].
• Facial Features: Some patients may exhibit characteristic facial features, although these are not universally present[2].
• Respiratory Distress: In severe cases, respiratory issues may arise due to central nervous system dysfunction affecting respiratory control[1].

Patient Characteristics

Genetic Background

Non-ketotic hyperglycinemia is typically inherited in an autosomal recessive manner, meaning that both parents must carry a copy of the mutated gene for a child to be affected. The most common genetic mutation associated with NKH occurs in the GLDC gene, which encodes the glycine decarboxylase enzyme[1][2].

Ethnic and Demographic Factors

While NKH can affect individuals from any ethnic background, certain populations may have a higher prevalence due to genetic factors. The condition is rare, with an estimated incidence of 1 in 100,000 live births[2].

Family History

A family history of metabolic disorders or neurological conditions may be present, which can aid in the diagnosis and management of NKH[1].

Conclusion

Non-ketotic hyperglycinemia is a complex metabolic disorder with significant neurological implications. Early recognition of its clinical presentation, including hypotonia, seizures, and developmental delays, is crucial for timely intervention and management. Genetic counseling may be beneficial for affected families, given the hereditary nature of the condition. Ongoing research into treatment options and supportive therapies continues to be essential for improving outcomes for individuals with NKH.

For further information or specific case management strategies, consulting with a metabolic specialist or genetic counselor is recommended.

Non-ketotic hyperglycinemia (NKH), classified under ICD-10 code E72.51, is a rare genetic disorder characterized by elevated levels of glycine in the body, leading to neurological issues. Understanding the alternative names and related terms for this condition can provide clarity for healthcare professionals and researchers. Below are some of the key terms associated with non-ketotic hyperglycinemia.

Alternative Names

1. Glycine Encephalopathy: This term is often used interchangeably with non-ketotic hyperglycinemia, emphasizing the neurological impact of elevated glycine levels on the brain.

2. Non-ketotic Hyperglycinemia Syndrome: This name highlights the syndrome aspect of the condition, indicating a collection of symptoms associated with the disorder.

3. Hyperglycinemia: While this term broadly refers to elevated glycine levels in the blood, it is sometimes used in the context of non-ketotic hyperglycinemia specifically.

4. Glycine Toxicity: This term may be used to describe the toxic effects of excessive glycine accumulation in the body, particularly in the central nervous system.

Related Terms

1. ICD-10 Code E72.51: The specific code used in the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) for billing and diagnostic purposes.

2. Inherited Metabolic Disorder: Non-ketotic hyperglycinemia is classified as an inherited metabolic disorder, indicating its genetic basis and the metabolic dysfunction involved.

3. Amino Acid Metabolism Disorders: This broader category includes various conditions related to the metabolism of amino acids, of which NKH is a specific example.

4. Newborn Screening: Non-ketotic hyperglycinemia is often included in newborn screening programs, as early detection is crucial for management and treatment.

5. Glycine Receptor Dysfunction: This term refers to the underlying mechanism of the disorder, where glycine receptors in the brain are affected, leading to neurological symptoms.

Conclusion

Understanding the alternative names and related terms for non-ketotic hyperglycinemia is essential for accurate diagnosis, treatment, and communication among healthcare providers. The condition's complexity and its implications for metabolic health underscore the importance of precise terminology in clinical settings. If you have further questions or need more specific information, feel free to ask!

Non-ketotic hyperglycinemia (NKH), classified under ICD-10 code E72.51, is a rare inherited metabolic disorder characterized by elevated levels of glycine in the body. The diagnosis of NKH involves a combination of clinical evaluation, biochemical testing, and genetic analysis. Below are the key criteria used for diagnosing this condition:

Clinical Presentation

1. Neurological Symptoms: Patients often present with a range of neurological symptoms, which may include:
   - Hypotonia (decreased muscle tone)
   - Seizures
   - Developmental delays
   - Coma in severe cases
   These symptoms typically manifest in the neonatal period or early infancy, although milder forms may present later in childhood[1].

2. Family History: A family history of metabolic disorders or similar neurological symptoms can be a significant indicator, as NKH is inherited in an autosomal recessive pattern[1].

Biochemical Testing

1. Plasma Glycine Levels: The primary diagnostic test for NKH is measuring the concentration of glycine in the plasma. Elevated levels of glycine (often > 200 µmol/L) are indicative of the disorder[1].

2. Urine Analysis: Urinary excretion of glycine may also be assessed. In NKH, urine may show elevated glycine levels, although this is less commonly used as a diagnostic criterion compared to plasma testing[1].

3. CSF Analysis: In some cases, cerebrospinal fluid (CSF) analysis may be performed to measure glycine levels, which can be significantly elevated in NKH compared to normal levels[1].

Genetic Testing

1. Molecular Genetic Testing: Confirmation of the diagnosis can be achieved through genetic testing to identify mutations in the GLDC gene, which encodes the glycine decarboxylase enzyme. Mutations in this gene are responsible for the impaired metabolism of glycine, leading to its accumulation[1].

2. Carrier Testing: In families with a known history of NKH, carrier testing can be performed to identify asymptomatic carriers of the disease-causing mutations[1].

Differential Diagnosis

It is essential to differentiate NKH from other metabolic disorders that may present with similar symptoms, such as:
- Urea cycle disorders
- Other organic acidemias
- Disorders of neurotransmitter metabolism

This differentiation often involves a comprehensive metabolic panel and additional specific tests to rule out these conditions[1].

Conclusion

The diagnosis of non-ketotic hyperglycinemia (ICD-10 code E72.51) relies on a combination of clinical assessment, biochemical tests, and genetic analysis. Early diagnosis is crucial for managing symptoms and providing appropriate care, as the condition can lead to significant neurological impairment if left untreated. If you suspect NKH, it is essential to consult a healthcare professional for a thorough evaluation and testing.

Non-ketotic hyperglycinemia (NKH), associated with ICD-10 code E72.51, is a rare metabolic disorder characterized by elevated levels of glycine in the blood and cerebrospinal fluid. This condition is primarily due to a deficiency in the glycine cleavage system, which is crucial for the metabolism of glycine. The management of NKH is complex and typically involves a multidisciplinary approach. Below, we explore standard treatment strategies for this condition.

Overview of Non-ketotic Hyperglycinemia

Non-ketotic hyperglycinemia is often diagnosed in infancy or early childhood and can lead to severe neurological symptoms, including seizures, developmental delays, and hypotonia. The severity of symptoms can vary widely among affected individuals, making personalized treatment plans essential.

Standard Treatment Approaches

1. Dietary Management

One of the primary strategies for managing NKH involves dietary modifications aimed at reducing glycine intake. This may include:

• Low-Protein Diet: Since glycine is an amino acid found in protein, a diet low in protein can help manage glycine levels. This requires careful planning to ensure that the child receives adequate nutrition while limiting glycine intake.
• Specialized Formulas: In some cases, specialized medical formulas that are low in glycine may be recommended to provide essential nutrients without exacerbating the condition.

2. Pharmacological Interventions

Several medications may be used to help manage symptoms and reduce glycine levels:

• Sodium Benzoate: This medication can help lower glycine levels by promoting its excretion through the urine. Sodium benzoate is often used in conjunction with dietary management.
• Glycine Antagonists: Research is ongoing into the use of glycine receptor antagonists, which may help mitigate the neurological effects of elevated glycine levels.

3. Supportive Therapies

Supportive care is crucial for individuals with NKH, particularly for managing neurological symptoms:

• Physical Therapy: To address hypotonia and improve motor skills, physical therapy can be beneficial.
• Occupational Therapy: This can help with daily living skills and promote independence as the child develops.
• Speech Therapy: For those experiencing speech and communication difficulties, speech therapy can provide essential support.

4. Monitoring and Follow-Up

Regular monitoring of glycine levels and neurological status is essential for individuals with NKH. This may involve:

• Routine Blood Tests: To check glycine levels and adjust dietary and pharmacological interventions as needed.
• Neurological Assessments: Ongoing evaluations by a neurologist to monitor developmental progress and adjust therapies accordingly.

5. Genetic Counseling

Since NKH is a genetic disorder, families may benefit from genetic counseling. This can provide insights into the inheritance patterns, risks for future pregnancies, and support resources available for affected families.

Conclusion

The management of non-ketotic hyperglycinemia requires a comprehensive and individualized approach, combining dietary management, pharmacological treatments, and supportive therapies. Early diagnosis and intervention are critical to improving outcomes for affected individuals. As research continues, new treatment modalities may emerge, offering hope for better management of this challenging condition. Regular follow-up and a multidisciplinary care team are essential to address the complex needs of patients with NKH effectively.