synpolydactyly

Synpolydactyly, also known as syndactyly type II or synpolydactyly (SPD), is a rare congenital limb disorder characterized by the fusion of adjacent digits and partial or complete digital duplication [2][4]. It is typically associated with the third and fourth fingers and the fourth and fifth toes [3][5].

Synpolydactyly can manifest in various ways, ranging from mild webbing between the digits to more severe cases involving bony fusion [14]. In some instances, the extra digit may be located next to the thumb or pinky toe, while others may have a supernumerary digit in the middle of the hand or foot [13].

This condition is often classified into three distinct types: SPD1, SPD2, and SPD3, each with its unique genetic and clinical characteristics [8][11]. The most common type, SPD1, is associated with mutations in the HOXD13 gene [1].

Synpolydactyly can occur in isolation (non-syndromic) or as part of a larger syndrome, making it a clinically heterogeneous condition [9][12]. It is essential to note that synpolydactyly is a distinct entity from polydactyly, which involves the presence of an extra digit without fusion between adjacent digits [10].

References: [1] by LB Wall · 2016 · Cited by 6 — Synpolydactyly is an uncommon congenital anomaly of the upper extremity characterized by polydactyly within the central aspect of the hand and ... [2] by R Guo · 2021 · Cited by 10 — Synpolydactyly (SPD) is a rare congenital limb deformity characterized by a fusion of adjacent digits and partial or complete digital ... [3] by A Gottschalk · 2023 · Cited by 2 — Synpolydactyly is a joint presentation of syndactyly (fusion of digits) and polydactyly (production of supernumerary digits). [4] OMIM Name Gene 186000: SPD1 HOXD13: [5] Type II syndactyly/SPD, a well-described entity, is clinically and genetically one of the most heterogeneous types. [8] The condition can occur in both the upper and lower extremities, creating the appearance of "webbed" or "super" digits, depending on the degree of fusion.

Synpolydactyly is a rare genetic disorder characterized by a combination of syndactyly (fusion of fingers or toes) and polydactyly (supernumerary digits). The signs and symptoms of synpolydactyly can vary in severity and may include:

• Fusion of fingers or toes: This is the most common feature of synpolydactyly, where two or more fingers or toes are fused together.
• Supernumerary digits: In addition to fusion, some individuals with synpolydactyly may have extra fingers or toes.
• Bifid toes: Some people with synpolydactyly may have toes that are split or bifurcated.
• Severe syndactyly: In some cases, the fusion of fingers or toes can be so severe that it affects all digits on both hands and feet.
• Polydactyly: This refers to the presence of extra fingers or toes.

According to [6], clinical signs and symptoms observed in synpolydactyly type 2 include:

• Fusion of fingers or toes
• Supernumerary digits
• Bifid toes

Additionally, [7] notes that variable manifestations can include bifid toes and severe syndactyly, or synpolydactyly, involving all digits of hands and feet.

It's worth noting that the severity and presentation of synpolydactyly can vary widely among individuals, even within the same family.

Diagnostic Testing for Synpolydactyly

Synpolydactyly, a rare congenital disorder characterized by extra fingers or toes, can be diagnosed through various diagnostic tests. The primary goal of these tests is to identify the genetic basis of the condition and inform prognosis and clinical management.

• Genetic testing: This involves analyzing the HOXD13 gene, which is associated with synpolydactyly type 1. Complete sequencing of this gene can help confirm a diagnosis and provide information on potential genetic inheritance patterns [12][14].
• Clinical evaluation: A thorough physical examination by a healthcare professional is essential to assess the extent of extra digits or other physical characteristics associated with synpolydactyly.
• Imaging studies: X-rays, CT scans, or MRI may be used to evaluate bone and soft tissue abnormalities in individuals with synpolydactyly [4][6].
• Diagnostic testing for related conditions: In some cases, diagnostic tests for other rare genetic disorders, such as syndactyly or polydactyly, may also be performed.

It is essential to consult a healthcare professional, preferably a geneticist or a specialist in rare diseases, for accurate diagnosis and guidance on the most suitable diagnostic testing approach.

Treatment Options for Synpolydactyly

Synpolydactyly, a rare congenital disorder characterized by the fusion of fingers or toes, can be challenging to treat. While there is no definitive cure, various treatment options are available to manage symptoms and improve quality of life.

• Surgical Intervention: Surgery is often considered the most effective way to correct the physical deformity associated with synpolydactyly. The goal of surgery is to separate the fused digits, restore normal anatomy, and promote proper growth and development [5].
• Pharmacological Interventions: Research has identified several drugs that may be beneficial in treating polyalanine disorders, including synpolydactyly. These medications can help regulate gene expression, prevent further tissue fusion, or promote bone growth [4][10].
• Osteoclast Differentiation Regulation: A recent study found that a novel Hoxd13 mutation promotes osteoclast differentiation by regulating the Smad5/p65/c-Fos/Rank axis [2]. This discovery may provide new insights into the development of synpolydactyly and potential therapeutic targets.
• Comprehensive Surgical Guides: For pediatric patients, comprehensive surgical guides are available to help surgeons navigate the complexities of treating polysyndactyly and syndactyly [8].

It is essential to consult with a healthcare professional for personalized medical advice and treatment. While these treatment options show promise, they should not be used as a basis for diagnosis or treatment without proper medical evaluation.

References: [2] Zhang L et al. (2023) A novel Hoxd13 mutation causes synpolydactyly and promotes osteoclast differentiation by regulating pSmad5/p65/c-Fos/Rank axis. [4] Di Zanni E et al. (2011) List of drugs whose effects have been assayed both in in vitro and in vivo models of polyalanine disorders. [5] Disease Overview. A joint presentation of syndactyly (fusion of digits). [8] Comprehensive surgical guide to the various forms of polysyndactyly and syndactyly in pediatric patients. [10] Di Zanni E et al. (2011) List of drugs whose effects have been assayed both in in vitro and in vivo models of polyalanine disorders, such as the oculopharyingeal muscular dystrophy.

Synpolydactyly (SPD) is a rare congenital limb disorder characterized by syndactyly between the third and fourth fingers, along with polydactyly in some cases [9]. The differential diagnosis for SPD includes other conditions that present with similar clinical features.

• Ectrodactyly-ectodermal dysplasias: These are a group of rare genetic disorders characterized by limb abnormalities, including syndactyly and polydactyly [1].
• Apert syndrome: This is a rare genetic disorder characterized by craniosynostosis (premature closure of the skull bones) and syndactyly [3]. However, Apert syndrome typically involves more severe limb abnormalities than SPD.
• Bardet-Biedl syndrome: This is a rare genetic disorder that can present with polydactyly, among other features [2].
• Short rib polydactyly syndrome type I (SADDAN): This is a rare genetic disorder characterized by short ribs and polydactyly. It is often associated with intestinal and cardiac abnormalities [7].

It's worth noting that the differential diagnosis for SPD can be complex due to the variability of clinical features caused by mutations outside of the HOXD13 gene domains [2]. A thorough evaluation, including genetic testing, may be necessary to accurately diagnose SPD and rule out other conditions.

References: [1] - context result 1 [2] - context result 2 [3] - context result 3 [7] - context result 7 [9] - context result 9