Ischiopatellar dysplasia

Synonyms	N/A
Pronounce
Field
Symptoms
Complications	N/A
Onset
Duration
Types	N/A
Causes
Risks
Diagnosis
Differential diagnosis
Prevention
Treatment
Medication
Prognosis	N/A
Frequency
Deaths

Ischiopatellar dysplasia is a rare autosomal dominant<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref> disorder characterized by a hypoplasia of the patellae as well as other bone anomalies, especially concerning the pelvis and feet.<ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref>

Signs and symptoms

Individuals affected by ischiopatellar dysplasia commonly have abnormalities of the patella and pelvic girdle,<ref>Scott JE, Taor WS. The “small patella” syndrome. J Bone Joint Surg Br. 1979;61:172–175.</ref> such as absent or delayed patellar and ischial ossification as well as infra-acetabular axe-cut notches.<ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref><ref>Kozlowski K, Nelson J. Small patella syndrome. Am J Med Genet. 1995;57:558–561.</ref><ref>Bongers EM, Van Bokhoven H, Van Thienen M, Kooyman M, Van Beersym S, Boetes C, Knoers N, Hamel B. The small patella syndrome: description of five cases from three families and examination of possible allelism with familial patella aplasia-hypoplasia and nail-patella syndrome. J Med Genet 2001;38:209-214.</ref> Patellae are typically absent or small in these individuals, when patellae are present they are small and laterally displaced or dislocated.<ref>Scott JE, Taor WS. The “small patella” syndrome. J Bone Joint Surg Br. 1979;61:172–175.</ref> In addition, abnormalities in other parts of their skeleton and dysmorphic features are common in those affected.<ref>Kozlowski K, Nelson J. Small patella syndrome. Am J Med Genet. 1995;57:558–561.</ref><ref>Azouz EM, Kozlowski K. Small patella syndrome: a bone dysplasia to recognize and differentiate from the nail-patella syndrome. Pediatr Radiol. 1997;27:432–435.</ref> Other features that have been identified in patients with ischiopatellar dysplasia include foot anomalies,<ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref> specifically flat feet (pes planus), syndactylism of the toes,<ref>Scott JE, Taor WS. The “small patella” syndrome. J Bone Joint Surg Br. 1979;61:172–175.</ref> short fourth and fifth toes, and a large gap between the first and second toes,<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref><ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref> femur anomalies,<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref> cleft palate,<ref>Kozlowski K, Nelson J. Small patella syndrome. Am J Med Genet. 1995;57:558–561.</ref> and craniofacial dysmorphisms.<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref><ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref>

Causes

Ischiopatellar dysplasia is often considered a familial condition.<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref><ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref><ref>Bongers EM, Van Bokhoven H, Van Thienen M, Kooyman M, Van Beersym S, Boetes C, Knoers N, Hamel B. The small patella syndrome: description of five cases from three families and examination of possible allelism with familial patella aplasia-hypoplasia and nail-patella syndrome. J Med Genet 2001;38:209-214.</ref><ref>Burckhardt A. The small patella syndrome. Z Orthop 1988;126:22–29.</ref> Ischiopatellar dysplasia has been identified on region 5.6 cM on chromosome 17q22. Mutations in the TBX4 (T-box protein 4) gene have been found to cause ischiopatellar dysplasia due to the essential role TBX4 plays in lower limb development since TBX4 is a transcription factor.<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref>

Diagnosis

Ischiopatellar dysplasia is usually identified through radiographic evidence since its characteristic changes are most notable in radiographic tests that indicate delayed boneage or absent ossification.<ref>Kozlowski K, Nelson J. Small patella syndrome. Am J Med Genet. 1995;57:558–561.</ref> A full skeletal survey should be performed on any patient that has an absent or hypoplastic patellae since they could potentially have ischiopatellar dysplasia. Magnetic resonance imaging (MRI) is especially helpful in the diagnosis of ischiopatellar syndrome and is recommended when an individual affected by ischiopatellar dysplasia has a traumatic injury to the knee.<ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref>

History

Ischiopatellar dysplasia is sometimes referred to as Scott-Taor syndrome after the researchers who first described ischiopatellar dysplasia as they recognized it in a family as an autosomal dominant disorder in 1979.<ref>Azouz EM, Kozlowski K. Small patella syndrome: a bone dysplasia to recognize and differentiate from the nail-patella syndrome. Pediatr Radiol. 1997;27:432–435.</ref> This finding was important as they were the first to note that it was a benign disorder that is separate from the more severe nail-patella syndrome.<ref>Scott JE, Taor WS. The “small patella” syndrome. J Bone Joint Surg Br. 1979;61:172–175.</ref> Other common names for ischiopatellar syndrome are small patella syndrome (SPS), since the patellae are often small or absent in patients who have this syndrome, and coxo-podo-patellaire syndrome.<ref>Bongers EM, Duijf PH, van Beersum SE, Schoots J, Van Kampen A, Burckhardt A, Hamel BC, Losan F, Hoefsloot LH, Yntema HG, Knoers NV, van Bokhoven H. Mutations in the human TBX4 gene cause small patella syndrome. Am J Hum Genet. 2004;74:1239–1248.</ref><ref>Kim H-S, Yoo J-H, Park N-H, Chang J-H, Ban Y-S, Song S-H. Magnetic Resonance Imaging Findings in Small Patella Syndrome. Knee Surgery & Related Research. 2016;28(1):75-78. </ref><ref>Kozlowski K, Nelson J. Small patella syndrome. Am J Med Genet. 1995;57:558–561.</ref>

References

   This article is a medical stub. You can help WikiMD by expanding it!

• 
  Diagram showing autosomal dominant inheritance pattern.