SHP-2 plays an important role in regulating expression of the Indian Hedgehog gene (IHH),  which is associated with differentiation in chondrocytes (specialized cells in cartilage tissue). Individuals affected by metachondromatosis generally demonstrate high levels of IHH expression, which is believed to be responsible for the tumor growth. Given that the mutation causes a loss of protein function and displays a dominant inheritance pattern, it is hypothesized that individuals homozygous for the disorder would display greater symptoms than heterozygous individuals, though insufficient data is available to evaluate these claims due to the rarity of the disease. Conversely, some heterozygous individuals have shown minimal effects, leading to the disorder’s designation as incompletely penetrant. The cause of this is not fully understood, but may be due to other factors influencing IHH expression. Diagnosis
Because of its rarity, metachondromatosis is often a difficult disease to recognize and diagnose. Diagnosis can be made based on clinical observations and radiographic findings as well as family history. Using radiographic methods, osteochondromas can be seen at the metaphyses of the short tubular bones, such as those in the hands and feet, pointing towards the joints. Enchondromas would also be visible along with the osteochondromas. The differential diagnosis includes hereditary multiple osteochondromas. This is a condition in which the long bones are primarily affected, and the lesions point away from the joint or growth plate. This may also result in the shortening or deformity of the affected bones. Since metachondromatosis is hereditary, genetic counseling can be offered to patients and their families.
Ocular albinism is a form of albinism which, in contrast to oculocutaneous albinism, presents primarily in the eyes. There are multiple forms of ocular albinism, which are clinically similar. : 865 Both known genes are on the X chromosome. When the term "autosomal recessive ocular albinism" ("AROA") is used, it usually refers to mild variants of oculocutaneous albinism rather than ocular albinism, which is X-linked. Types
References
External links

GeneReviews/NCBI/NIH/UW entry on Ocular Albinism, X-Linked