distal arthrogryposis type 2B1

Distal Arthrogryposis Type 2B1 (DA2B1) Description

Distal arthrogryposis type 2B1, also known as Sheldon-Hall syndrome, is a genetic disorder characterized by joint contractures in the hands and feet. This condition is part of a larger group of disorders known as distal arthrogryposis.

Key Features:

• Joint deformities (contractures) that restrict movement in the hands and feet
• Distinctive facial features, such as down-slanting palpebral fissures and nasolabial folds
• Clenched fist, overlapping fingers, camptodactyly, ulnar deviation, and positional foot deformities from birth

Genetic Aspect:

• DA2B1 is caused by a heterozygous mutation in the TNNI2 gene on chromosome 11p15
• Autosomal dominant inheritance pattern, meaning that a single copy of the mutated gene is sufficient to cause the condition

Prevalence and Diagnosis:

• A relatively rare disorder, with an estimated occurrence rate of 1 in 3,000 live births
• Diagnosis typically involves clinical evaluation and genetic testing to confirm the presence of the TNNI2 mutation.

Note: The information provided above is based on the search results within the context. If you have any specific questions or would like further clarification, please feel free to ask!

Distal arthrogryposis type 2B1, also known as Sheldon-Hall syndrome, is a genetic disorder characterized by joint contractures in the hands and feet. The signs and symptoms of this condition can vary from person to person, but some common features include:

• Joint deformities: Contractures or deformities in the joints of the hands and feet, which can restrict movement.
• Clenched fist: A clenched fist is a characteristic feature of distal arthrogryposis type 2B1. This occurs when the fingers are flexed and cannot be fully extended.
• Overlapping fingers: The fingers may overlap or be positioned in a way that makes it difficult to extend them fully.
• Camptodactyly: A condition where one or more fingers are permanently bent, making it difficult to straighten them.
• Ulnar deviation: The wrist and hand may deviate towards the ulnar side (the side away from the center of the body).
• Positional foot deformities: The feet may be positioned in a way that makes it difficult to walk or stand normally.

In addition to these physical symptoms, distal arthrogryposis type 2B1 is also associated with distinctive facial features, such as:

• Down-slanting palpebral fissures: The eyes are slanted downwards.
• Nasolabial folds: Deep creases or folds on the sides of the nose and mouth.

It's worth noting that the severity and presentation of distal arthrogryposis type 2B1 can vary widely from person to person, even within the same family. [11][12]

References: [11] - Distal arthrogryposis type 2B1 is a genetic disorder characterized by joint contractures in the hands and feet, along with distinctive facial features such as down-slanting palpebral fissures and nasolabial folds. [12] - Symptoms & Phenotypes for Arthrogryposis, Distal, Type 2b1.

Diagnostic Tests for Distal Arthrogryposis Type 2B1

Distal arthrogryposis type 2B1, also known as Sheldon-Hall syndrome, is a genetic disorder characterized by joint contractures in the hands and feet. Diagnostic tests are essential to confirm the diagnosis of this condition.

Genetic Tests

• Sequence analysis of the entire coding region: This test involves analyzing the TNNI2 gene to identify any mutations that may be causing the condition [1, 3, 4].
• Next-Generation (NGS)/Massively Parallel Sequencing (MPS): This is a comprehensive genetic test that analyzes multiple genes simultaneously, including the TNNI2 gene [6].
• Deletion/duplication analysis: This test identifies any deletions or duplications in the TNNI2 gene that may be contributing to the condition [12].

Clinical Molecular Genetics Tests

• Sequence analysis of the entire coding region: This test is offered by MedGene and involves analyzing the TNNI2 gene to identify any mutations that may be causing the condition [14].
• Deletion/duplication analysis, PCR with allele specific hybridization: This test is offered by Centogene AG - the Rare Disease Company and identifies any deletions or duplications in the TNNI2 gene that may be contributing to the condition [12].

Other Diagnostic Features

• Camptodactyly or pseudocamptodactyly: This is a characteristic feature of distal arthrogryposis type 2B1, where there is a flexion deformity in one or more fingers [8, 9].
• Hypoplastic or absent flexion creases: This is another diagnostic feature of the condition, where there are reduced or absent flexion creases in the hands and feet [9].

It's essential to consult with a healthcare professional for accurate diagnosis and treatment. They will determine the best course of action based on individual circumstances.

References:

[1] Quest Diagnostics Incorporated [3] Centogene AG - the Rare Disease Company [4] MedGene [6] Centogene AG - the Rare Disease Company [8] Charlotte Radiology [9] CIS (Charlotte Radiology and Atrium Health) [12] Centogene AG - the Rare Disease Company [14] MedGene

Treatment Options for Distal Arthrogryposis Type 2B1

Distal arthrogryposis type 2B1, also known as Sheldon-Hall syndrome, is a rare genetic disorder characterized by joint deformities that restrict movement in the hands and feet. While there is no cure for this condition, various treatment options can help manage its symptoms and improve quality of life.

Medications

According to recent studies [4], treatment with cholinesterase inhibitors or amifampridine may be helpful in managing the symptoms of distal arthrogryposis type 2B1. These medications can help improve muscle tone and reduce contractures, thereby enhancing mobility and function.

• Cholinesterase inhibitors work by increasing the levels of acetylcholine, a neurotransmitter that plays a crucial role in muscle contraction [4].
• Amifampridine is a potassium channel blocker that can help improve muscle strength and reduce fatigue [4].

Other Treatment Options

In addition to medications, other treatment options for distal arthrogryposis type 2B1 include:

• Physical therapy: A multidisciplinary team focusing on intensive physiotherapy and rehabilitation can help improve mobility and function in affected individuals [8].
• Bracing and surgical interventions: Use of braces, casts, or surgical treatment can correct limb contractures and improve joint alignment [9].

Early Intervention

Early initiation of treatment is essential for managing the symptoms of distal arthrogryposis type 2B1. A multidisciplinary team approach focusing on intensive physiotherapy and rehabilitation, bracing, and surgical interventions can help improve outcomes and enhance quality of life.

References:

[4] Engel et al., (2015) - Treatment with cholinesterase inhibitors or amifampridine may be helpful. [8] Early initiation of treatment involving a multidisciplinary team focusing on intensive physiotherapy and rehabilitation, bracing and surgical interventions. [9] Use of braces, casts, or surgical treatment for correcting limb contractures. Physical therapy to improve the movements of hands and limbs.

Distal arthrogryposis type 2B (DA2B) is a congenital disorder characterized by joint deformities in the hands and feet, with features such as clenched fist, overlapping fingers, and limited mobility. When considering the differential diagnosis of DA2B, several conditions should be taken into account.

• Freeman-Sheldon Syndrome: This syndrome is a type of genetic disorder that affects the muscles and joints, leading to characteristic facial features, hypotonia, and joint deformities similar to those seen in DA2B [8].
• Sheldon-Hall Syndrome: Another condition that shares overlapping features with DA2B is Sheldon-Hall syndrome. The differential diagnosis of this syndrome includes Freeman-Sheldon Syndrome, among other conditions [8].

It's essential to note that the genetic cause of DA2B can vary, and in some cases, it may be caused by mutations in genes such as TPM2, MYBPC1, or TNNT3 [9]. Therefore, a comprehensive evaluation, including genetic testing, is necessary to accurately diagnose and differentiate DA2B from other conditions.

References: [8] - The differential diagnosis of Sheldon-Hall syndrome includes: Freeman-Sheldon Syndrome: Freeman-Sheldon syndrome is a type of genetic disorder that affects the muscles and joints. [9] - Distal arthrogryposis can be caused by mutations in several genes. Type 1 is mostly due to altered TPM2, MYBPC1 or TNNT3 genes. In some cases, the genetic cause may vary.