Discovering the Gene(s) Causing Developmental Dysplasia of the Hip (DDH)
Discovering the Gene(s) Causing Developmental Dysplasia of the Hip (DDH)
The primary objective of the study is to find the gene(s) responsible for causing DDH. The
 secondary objective of the study is to determine the mode of genetic transmission of DDH.
Developmental dysplasia of the hip (DDH), formerly known as Congenital Dislocation of the Hip
 (CDH) is a relatively common disorder that can lead to early onset arthritis of the hip. It
 is believed that DDH is the major cause of arthritis of the hip in young patients. The
 majority of patients with DDH are unaware of their condition. Only a very small number of
 these patients with the extremely severe form of the disease (dislocated hip) are identified
 at birth. The remaining patients usually seek help when severe arthritis is present and joint
 preservation treatment is not possible. The exact etiology of this condition remains elusive.
 Based on reports in the literature, DDH is believed to have a genetic basis.

 Dr. Javad Parvizi at Rothman Institute (RT) in Philadelphia has extensive experience with
 this condition because their center provides joint preservation procedures such as pelvic and
 femoral osteotomy. They also have extensive experience with hip replacement in these
 patients. They are aware of some families with many affected individuals. Close history
 taking and examination of these patients has suggested that there may indeed be a genetic
 basis for DDH. Based on our findings so far, we believe that a dominant pattern of
 inheritance may exist, implying that this disorder may be inherited in a Mendelian manner
 (Single gene disorder).

 Furthermore, Dr. Parvizi's group have documented a peculiar pattern of dominant inheritance
 in which all affected males give rise to only affected female children, suggesting that the
 disorder may be inherited as an X-linked dominant trait. X-linked dominant is the mode of
 inheritance in which a gene on the X chromosome is dominant. The X-linked dominant
 inheritance may in part account for the large number of females affected with the trait.
 Understanding the inheritance mechanism of this disease will allow better genetic counseling
 and monitoring of affected individuals and their families.

 The reason behind this study is to investigate the possible genetic inheritance of the
 disease. Knowing this information will allow us to test patients for the disease early and
 before arthritis develops. In addition it is possible that better treatments may be designed
 based on this knowledge.

 DDH is a relatively common condition. Although the most severe form of DDH is usually
 diagnosed during birth (dislocated hip), the majority (>80%) of patients with this condition
 do not even know that they suffer from this disease and usually discover their condition when
 disabling arthritis of the hip develops in early adulthood.
Inclusion Criteria:

 -  All patients with radiographic and clinical diagnosis of DDH will be included.

 Exclusion Criteria:

 -  Other forms of arthritis:

 -  osteoarthritis

 -  inflammatory arthropathies

 -  vascular necrosis