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Pseudopseudohypoparathyroidism (PPHP) is an inherited condition that causes short stature, round face, and short hand bones. PPHP causes joints and other soft tissues in the body to harden. It also affects how bones are formed. As a result, PPHP can cause bone, joint, and nerve damage, and this damage can cause lasting pain. Some people with PPHP (10%) also have learning disability. PHPP is caused by mutations in the GNAS gene and is inherited in an autosomal dominant fashion. This condition is usually inherited from the father (genomic imprinting).
PPHP is genetically related to pseudohypoparathyroidism type Ia (PHP-1a). Signs and symptoms are similar, however people with PPHP do not show resistance to parathyroid hormone while people with PHP-1a do. Obesity is characteristic for PHP-1a and may be severe, while obesity is less prominent and may be absent among people with PPHP. Both PHP-1a and PPHP are caused by mutations that affect the function of the GNAS gene. But people who inherit the mutation from their mother develop PHP-1a; whereas those who inherit the mutation from their father develop PPHP.
Source: GARD Last updated on 05-01-20
Diagnosis of PPHP is based on the presence of features of Albright hereditary osteodystrophy (AHO) without parathyroid hormone (PTH) resistance. If there are features of AHO and resistance to PTH a different form of pseudohypoparathyroidism (PHP) will be considered. Other forms of PHP are usually ruled out by blood tests including serum calcium, phosphate and PTH. X-rays will show shortening of the fourth metacarpal (long bone of the hand) and advanced bone age. All metacarpals and metatarsals (long bones of the foot) may be affected. The diagnosis is confirmed by genetic testing identifying a mutation or change in the GNAS gene.
Last updated on 05-01-20
Yes. Pseudopseudohypoparathyroidism (PPHP) can cause joints and other soft tissues in the body to harden. It also affects how bones are formed. As a result, PPHP can cause bone, joint, and nerve damage, and this damage can cause lasting pain.
Examples of painful bone, joint, and nerve injuries that have been described in individual patients with PPHP include:
Synovial osteochondromatosis - A joint disorder where cartilage forms in the lining of the joint (synovium). Pieces of cartilage may enlarge, break off into the joint space, and harden, forming loose bodies. People with this disorder often report having experienced several years of joint pain, swelling and stiffness. If allowed to continue, the condition can limit range of motion in the affected joint. Treatment may involve surgery.
Ossification of the posterior longitudinal ligament (OPLL) – A hardening of the band of tissue that runs up and down behind the spine and inside the spinal canal. This can cause narrowing of the spinal canal and increased pressure on the spinal nerves. Signs and symptoms may include numbness, weakness, cramping, general pain in the arm(s), or general or shooting pain in the leg(s). Symptoms slowly worsen over time.
Cervical myelopathy – A narrowing of the spinal column. This can cause many different symptoms, including pain, numbness, and weakness. OPLL can cause cervical myelopathy.
Avascular necrosis - The death of bone tissue due to a lack of blood supply. This condition can cause mild to severe pain.
Intracranial calcification - Calcium deposits in the brain, most often in the basal ganglia. The basal ganglia are structures deep within the brain that help start and control movement. These calcifications may cause involuntary movements (extrapyramidal symptoms).
Why complications like these sometimes happen to people with PPHP is not clear. Mutations in the gene GNAS cause PPHP. GNAS is being studied for its role in causing abnormal bone growth in soft tissues (i.e., progressive osseous heteroplasia). These GNAS effects may explain why painful tissue, joint, and nerve damage occurs in people with PPHP.
We strongly recommend that you speak with your healthcare provider regarding the symptoms you have been experiencing, and to discuss your testing and treatment options.
In addition, the following organizations provide information and support to people who live with chronic pain and may be a helpful resource.
Last updated on 05-01-20
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