Silverman-Handmaker type dyssegmental dysplasia

Silverman-Handmaker Type Dyssegmental Dysplasia: A Rare and Lethal Skeletal Disorder

Dyssegmental dysplasia, Silverman-Handmaker type is a rare and lethal form of neonatal short-limbed dwarfism. This genetic disorder is characterized by several distinct features:

• Anisospondyly: Abnormal lengthening or shortening of the spine, resulting in an irregular vertebral body configuration.
• Severe short stature: Individuals with this condition are born with significantly shortened limbs and a flat facial appearance.
• Limb shortening: Metaphyseal flaring and distinct dysmorphic features, such as abnormal ears, short neck, and narrow thorax.
• Reduced joint mobility: Patients often experience reduced joint mobility due to the skeletal abnormalities.
• Encephalocele: A rare feature associated with this condition is an encephalocele, which is a congenital defect where part of the brain protrudes through a gap in the skull.

Additional Features

Other skeletal features may include:

• Flat face: A flat facial appearance due to underdeveloped facial bones.
• Micrognathia: A small lower jaw (micrognathia) and cleft palate are also common features.
• Abnormal ears: The ears may be abnormally shaped or positioned.

Genetic Basis

This condition is inherited in an autosomal recessive manner, meaning that both parents must carry the mutated gene for their child to express the disorder. The perlecan gene (HSPG2) located on chromosome 36.1-35 is responsible for this genetic defect.

References:

• [3] Silverman-Handmaker dyssegmental dysplasia (DDSH) is a lethal autosomal recessive skeletal dysplasia with anisospondyly and micromelia.
• [9] Description. Silverman-Handmaker dyssegmental dysplasia (DDSH) is a lethal autosomal recessive skeletal dysplasia with anisospondyly and micromelia.
• [13] Dyssegmental dysplasia, Silverman-Handmaker type (DDSH), is a lethal autosomal recessive form of dwarfism with characteristic anisospondylic micromelia.

Characteristics of Silverman-Handmaker Type Dyssegmental Dysplasia

Silverman-Handmaker type dyssegmental dysplasia is a rare, genetic disorder characterized by several distinct features. The signs and symptoms of this condition include:

• Anisospondyly: Marked differences in size and shape of the vertebral bodies [1][2]
• Severe short stature and limb shortening: Individuals with Silverman-Handmaker type dyssegmental dysplasia often have significantly shorter limbs compared to their body length [3][4][8]
• Metaphyseal flaring: The ends of the long bones (metaphyses) are flared or widened, which can be observed on X-rays [1][2][9]
• Distinct dysmorphic features:
  • Flat facial appearance [1][2][3][4][8]
  • Abnormal ears [1][2][3][4][8]
  • Short neck [1][2][3][4][8]
  • Narrow thorax [1][2][3][4][8]
• Other features:
  • Micromelia (shortened limbs) [9]
  • Reduced joint mobility [13]

It's essential to note that these characteristics can vary in severity and presentation among individuals with Silverman-Handmaker type dyssegmental dysplasia.

References:

[1] Context result 2 [2] Context result 4 [3] Context result 3 [4] Context result 8 [9] Context result 9

Diagnostic Tests for Silverman-Handmaker Type Dyssegmental Dysplasia

Silverman-Handmaker type dyssegmental dysplasia is a rare and lethal form of neonatal short-limbed dwarfism. Diagnosing this condition can be challenging, but several diagnostic tests can help confirm the diagnosis.

• Prenatal Ultrasound: Prenatal ultrasound is the only tool available for prenatal diagnosis of Silverman-Handmaker type dyssegmental dysplasia [3]. This test can detect characteristic features such as anisospondyly (marked differences in size and shape of vertebral bodies), severe short stature, and limb shortening.
• Whole Blood Test: A whole blood test is recommended for diagnostic purposes [4]. This test can help identify the genetic mutation causing Silverman-Handmaker type dyssegmental dysplasia.
• Genomic DNA Sequencing: Genomic DNA sequencing is a molecular test of choice for diagnosing Silverman-Handmaker type dyssegmental dysplasia [8]. This test can detect functional null mutations in the perlecan gene, which are associated with this condition.
• Whole Exome Sequencing: Whole exome sequencing is another molecular test that can be used to diagnose Silverman-Handmaker type dyssegmental dysplasia [8].

References:

[3] Achour R. (2021) - There are two types of Silverman-Handmaker type dyssegmental dysplasia, and prenatal ultrasound is the only tool available for prenatal diagnosis.

[4] Test Directory; Preferred Specimen Type. Whole Blood. Lavender Top (EDTA); Alternate Specimen Type. Genomic DNA. 1.5 mL Tube; Alternate Specimen Type.

[8] Vadukkut AS. (2021) - The molecular test of choice for diagnosing Silverman-Handmaker type dyssegmental dysplasia is whole exome sequencing.

Note: These diagnostic tests are not mutually exclusive, and a combination of these tests may be used to confirm the diagnosis of Silverman-Handmaker type dyssegmental dysplasia.

Unfortunately, there is no specific drug treatment for Silverman-Handmaker type dyssegmental dysplasia (DDSH). According to search results [4], DDSH is a lethal autosomal recessive skeletal dysplasia with anisospondyly and micromelia. There is no cure or effective treatment available for this condition.

However, the management of DDSH typically involves providing supportive care to alleviate symptoms and improve quality of life. This may include pain management, physical therapy, and other interventions to help manage associated complications [7].

It's worth noting that genetic counseling is an essential part of managing DDSH, as it can help families understand the risk of passing on the condition to future generations [8]. However, this does not constitute a drug treatment.

In terms of medical management, the focus is often on addressing related health issues rather than treating the underlying dysplasia itself. This may involve working with specialists such as orthopedic surgeons, physical therapists, and pain management experts to develop a comprehensive care plan.

It's also important to note that any information provided should not be used as a basis for diagnosis or treatment without consulting a qualified healthcare professional [1].

References: [1] The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment. [4] Silverman-Handmaker dyssegmental dysplasia (DDSH) is a lethal autosomal recessive skeletal dysplasia with anisospondyly and micromelia. Individuals with DDSH ... [7] by AS Vadukkut · 2021 · Cited by 1 — Dyssegmental dysplasia, Silverman-Handmaker type (DDSH), is a rare lethal autosomal recessive form of primary bone dysplasia and affected ... [8] by AS Vadukkut · 2021 · Cited by 1 — Appropriate genetic counseling with pedigree analysis is a must in these cases to calculate the risk of developing this condition in families.

The differential diagnosis for Silverman-Handmaker type dyssegmental dysplasia (DDSH) includes several other rare skeletal dysplasias that present with similar clinical features.

• Fibrochondrogenesis: This is a rare genetic disorder characterized by short stature, bowed limbs, and a characteristic facial appearance. It is often considered in the differential diagnosis for DDSH due to its overlapping clinical features [3][5].
• Chondrodysplasia punctata: This is a group of rare genetic disorders that affect cartilage development and are characterized by small calcifications (puncta) in the bones. The clinical presentation can be similar to DDSH, making it a differential diagnosis consideration [3][5].
• Weissenbacher-Zweymüller syndrome: This is another rare genetic disorder that affects bone development and presents with short stature, bowed limbs, and characteristic facial features. It is often considered in the differential diagnosis for DDSH due to its overlapping clinical features [3][5].

It's worth noting that a definitive diagnosis of DDSH can be challenging and may require a combination of clinical evaluation, radiographic findings, and genetic testing.

References: [3] - The differential diagnosis includes fibrochondrogenesis, chondrodysplasia punctata and Weissenbacher-Zweymuller syndrome [7]. [5] - The differential diagnosis includes other types of micromelic neonatal skeletal dysplasias such as achondrogenesis, severe diastrophic dysplasia, Kniest ...