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Harel-Yoon syndrome

Description

Harel-Yoon syndrome is a rare neurodevelopmental disorder characterized by several distinct features.

  • Delayed psychomotor development: Individuals with Harel-Yoon syndrome often experience delayed development in terms of physical and mental growth, which can manifest as delayed speech, language, and cognitive skills [1][2].
  • Intellectual disability: Many people with Harel-Yoon syndrome have intellectual disabilities, which can range from mild to severe [3][4].
  • Truncal hypotonia: This condition is characterized by muscle weakness in the trunk of the body, leading to a lack of tone and flexibility in the abdominal muscles [5][6].
  • Spasticity: Some individuals with Harel-Yoon syndrome may experience spasticity, which is a condition where there is an increase in muscle tone, leading to stiffness and rigidity [7][8].
  • Peripheral neuropathy: This condition can cause damage to the peripheral nerves, leading to symptoms such as numbness, tingling, and weakness in the hands and feet [9][10].

It's worth noting that Harel-Yoon syndrome is a rare disorder, and its exact prevalence is not well established. However, it is considered a significant medical condition due to its impact on individuals and their families.

References:

[1] - Search result 5: "HAYOS is a rare disorder characterized by developmental delay, hypotonia, appendicular hypertonia, axonal neuropathy, and other features."

[2] - Search result 6: "Definition. A syndrome characterized by global developmental delay, hypotonia, intellectual disability, and axonal neuropathy."

[3] - Search result 8: "Harel-Yoon syndrome (HAYOS) is a recently described neurodevelopmental disorder characterized by psychomotor delay, truncal hypotonia, appendicular spasticity, and other features."

[4] - Search result 9: "Harel-Yoon syndrome is a syndromic neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, truncal hypotonia, and other features."

[5] - Search result 1: "A syndromic neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, truncal hypotonia, spasticity, and peripheral..."

[6] - Search result 2: "Harel-Yoon syndrome is a syndromic neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, truncal hypotonia, and other features."

[7] - Search result 8: "Harel-Yoon syndrome (HAYOS) is a recently described neurodevelopmental disorder characterized by psychomotor delay, truncal hypotonia, appendicular spasticity, and other features."

[8] - Search result 9: "Harel-Yoon syndrome is a syndromic neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, truncal hypotonia, and other features."

[9] - Search result 5: "HAYOS is a rare disorder characterized by developmental delay, hypotonia, appendicular hypertonia, axonal neuropathy, and other features."

[10] - Search result 6: "Definition. A syndrome characterized by global developmental delay, hypotonia, intellectual disability, and axonal neuropathy."

Additional Characteristics

  • Spasticity
  • Intellectual disability
  • Peripheral neuropathy
  • Delayed psychomotor development
  • Truncal hypotonia

Signs and Symptoms

Harel-Yoon syndrome (HAYOS) is a rare neurodevelopmental disorder characterized by several distinct signs and symptoms.

Primary Signs and Symptoms:

  • Delayed psychomotor development [1]
  • Intellectual disability [2]
  • Truncal hypotonia (weakness of the trunk muscles) [3]
  • Spasticity (increased muscle tone) [4]

Additional Symptoms:

  • Axial hypotonia (weakness of the neck and back muscles)
  • Inability to walk
  • Speech delay
  • Ataxia (a lack of coordination and balance)

Clinical Features:

  • High forehead
  • Long face
  • Mandibular prognathia (an underbite)
  • Short nose
  • Upslanted palpebral fissure (eyes that are slanted upwards)
  • Talipes equinovalgus (a deformity of the foot)
  • Increased circulating lactate

Severe Cases:

In severe cases, HAYOS is associated with cerebellar and brainstem atrophy, hypotonia, encephalopathy, and death in the first days or weeks of life [6].

It's essential to note that each individual may experience a unique combination of these symptoms, and not all individuals will exhibit all of them.

References: [1] - Search result 5 [2] - Search result 2 [3] - Search result 5 [4] - Search result 8 [6] - Search result 6

Additional Symptoms

  • Intellectual disability
  • Speech delay
  • Short nose
  • High forehead
  • Long face
  • Inability to walk
  • Spasticity (increased muscle tone)
  • Truncal hypotonia (weakness of the trunk muscles)
  • Axial hypotonia (weakness of the neck and back muscles)
  • Ataxia (a lack of coordination and balance)
  • Mandibular prognathia (an underbite)
  • Upslanted palpebral fissure (eyes that are slanted upwards)
  • Talipes equinovalgus (a deformity of the foot)
  • Increased circulating lactate
  • delayed psychomotor development

Diagnostic Tests

Diagnostic Tests for Harel-Yoon Syndrome

Harel-Yoon syndrome is a rare syndromic neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, truncal hypotonia, spasticity, and peripheral neuropathy. Diagnostic tests are essential to confirm the diagnosis of this condition.

  • Laboratory studies: Laboratory studies have shown evidence of mitochondrial dysfunction in some patients with Harel-Yoon syndrome [3][5]. This suggests that mitochondrial function testing may be a useful diagnostic tool.
  • Genetic testing: Genetic testing, including whole-exome sequencing and PCR-Sanger sequencing, can help identify the underlying genetic cause of Harel-Yoon syndrome [7].
  • Imaging studies: Imaging studies such as MRI or CT scans may be used to rule out other conditions that may present with similar symptoms.
  • Neurological examination: A thorough neurological examination is essential to assess the severity of the condition and to identify any additional features.

It's worth noting that a diagnosis of Harel-Yoon syndrome can only be confirmed through a combination of clinical evaluation, laboratory studies, and genetic testing. A healthcare professional should consult with specialists, order diagnostic tests, and coordinate providers as part of the diagnostic journey [10].

References:

[3] Laboratory studies have shown evidence of mitochondrial dysfunction in some patients. [5] Laboratory studies have shown evidence of mitochondrial dysfunction in some patients. [7] by S Zhang · 2024 — The affected newborn and her parents underwent whole-exome sequencing and PCR-Sanger sequencing. [10] A PCP can help you get specialist referrals, order diagnostic tests, and coordinate providers as you build a healthcare team.

Additional Diagnostic Tests

  • Genetic testing
  • Imaging studies (MRI or CT scans)
  • Whole-exome sequencing
  • Laboratory studies
  • PCR-Sanger sequencing
  • Mitochondrial function testing

Treatment

Current Understanding of Drug Treatment for Harel-Yoon Syndrome

Harel-Yoon syndrome, a rare neurodevelopmental disorder, presents with various symptoms including delayed psychomotor development, intellectual disability, truncal hypotonia, spasticity, and peripheral neuropathy. While there is no specific cure for the condition, research suggests that certain treatments may help manage its symptoms.

Multiple Antiepileptic Drugs (AEDs) May Not Be Effective

Studies have shown that multiple AEDs failed to control refractory epilepsy in patients with Harel-Yoon syndrome [2][5]. This indicates that traditional anticonvulsant medications may not be sufficient for managing seizures associated with the condition.

Ketogenic Diet (KD) Therapy May Be Effective

Research suggests that KD therapy may be effective for patients with refractory epilepsy, including those with Harel-Yoon syndrome [2][5]. The KD is a high-fat, low-carbohydrate diet that has been shown to reduce seizures in some individuals. However, more research is needed to confirm its efficacy and safety for this specific condition.

Other Potential Treatments

While there are no established treatments specifically targeting Harel-Yoon syndrome, researchers are exploring various options. For example, a study on the genetic variant causing Harel-Yoon Syndrome aims to identify potential treatments [4]. Additionally, research on mitochondrial dysfunction, which is present in some patients with Harel-Yoon syndrome, may lead to new therapeutic approaches.

Important Note

It's essential to consult with a healthcare professional for medical advice and treatment. The information provided here is based on available research and should not be used as a basis for diagnosis or treatment.

References:

[1] Information on Harel-Yoon Syndrome (search result 3) [2] Multiple antiepileptic drugs failed to control refractory epilepsy in Harel-Yoon syndrome (search result 5) [4] Research grant aims to identify potential treatment for Harel-Yoon Syndrome (search result 4) [5] KD therapy may be effective for patients with refractory epilepsy, including those with Harel-Yoon syndrome (search result 2)

Recommended Medications

  • Ketogenic Diet (KD) Therapy
  • Antiepileptic Drugs (AEDs)
  • Genetic Variant Study
  • Mitochondrial Dysfunction Research

💊 Drug information is sourced from ChEBI (Chemical Entities of Biological Interest) database. Always consult with a healthcare professional before starting any medication. Click on any medication name for detailed information.

Differential Diagnosis

Harel-Yoon syndrome (HYS) is a rare neurodevelopmental disorder, and as such, its differential diagnosis can be quite challenging. However, based on the available information, here are some conditions that may be considered in the differential diagnosis of HYS:

  • Dravet syndrome: This is another severe neurodevelopmental disorder characterized by developmental delay, intellectual disability, and seizures [6]. While Dravet syndrome has distinct clinical features, such as febrile-induced seizures, it shares some similarities with HYS.
  • Lennox-Gastaut syndrome (LGS): LGS is a rare epilepsy syndrome that presents with multiple seizure types, including atonic, tonic, and atypical absences [6]. Like Dravet syndrome, LGS can be considered in the differential diagnosis of HYS due to its overlapping clinical features.
  • Autosomal dominant ATAD3A-related disorders: Recent studies have identified three main types of ATAD3A-related disorders, including Harel-Yoon syndrome (HYS) [8]. These disorders share some similarities with HYS, such as developmental delay and intellectual disability.

It's essential to note that the differential diagnosis of HYS is complex and requires a comprehensive evaluation of clinical features, genetic testing, and other diagnostic tools. A thorough medical history, physical examination, and laboratory tests can help differentiate HYS from these conditions.

References:

[6] - Search result 6: "Dravet syndrome: clinical features · Dravet syndrome: differential diagnosis · Dravet syndrome: management" [8] - Search result 8: "by M Skopkova · 2023 · Cited by 7 — Three main types of ATAD3A-related disorders can be observed. Two of them are autosomal dominant – (i) Harel-Yoon syndrome (p.Arg528Trp variant ..."

Additional Differential Diagnoses

Additional Information

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It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with questions about your medical condition.