If you or your child has Perthes, you probably have wondered if the disease is genetic or inheritable. A recent article published in the Journal of Pediatrics, the official Journal of the American Academy of Pediatrics, looks into the chance of identical or fraternal twins having Perthes disease. If a high number of identical or fraternal twins both had Perthes, this finding would suggest a strong genetic cause for the disease. In the past, research has suggested that there is potential genetic cause to twins with Perthes, however the number of twins studied were small in number. This particular study analyzed 81 twin pairs with 10 pairs being identical twins and 51 fraternal twins. The study examined all twin pairs from the Danish Twin Registry (DTR), in which at least one of the siblings was diagnosed with Perthes disease. The DTR records all twins who are born in Denmark. From that group, the twins with Perthes were identified from various health records. From the 81 sets of twins, only 4 pairs of twins both had Perthes. Two sets were fraternal, and the other two were unknown to whether they were fraternal or identical. The study did show clustering of Perthes within a small number of families, however, the authors thought that this was due to each twin growing up or being exposed to similar environments. From previous studies, potential environmental factors that have been identified to be associated with Perthes include passive smoking and nutritional deprivation. In conclusion, the study found no evidence to support genetic cause for Perthes disease.

Although the study did not give a direct answer to the cause of Perthes, it provided more information into the many factors that can cause the disease. Since the study suggested family clustering, if one child is diagnosed with the disease, then the other children within the family have a slightly higher probability of having Perthes as well. Although the overall risk is still extremely low, it is important to pay close attention to signs of hip, knee, or thigh pain and limping in other children in the family.