Albright hereditary osteodystrophy

Albright Hereditary Osteodystrophy

Albright Hereditary Osteodystrophy (AHO) is a rare genetic disorder characterized by a constellation of physical and biochemical abnormalities. It is primarily associated with resistance to parathyroid hormone (PTH), leading to a condition known as pseudohypoparathyroidism. AHO is named after Fuller Albright, an American endocrinologist who first described the condition.

Clinical Features

Individuals with Albright Hereditary Osteodystrophy typically present with a variety of clinical features, which may include:

• Short Stature: Affected individuals often have a shorter than average height.
• Obesity: There is a tendency towards obesity, particularly in childhood.
• Brachydactyly: Shortening of the bones in the hands and feet, particularly the metacarpals and metatarsals.
• Subcutaneous Calcifications: Calcium deposits under the skin are common.
• Round Face: A rounded facial appearance is often noted.

Pathophysiology

The underlying cause of Albright Hereditary Osteodystrophy is typically a mutation in the GNAS gene, which encodes the alpha subunit of the stimulatory G protein (Gs alpha). This protein is involved in the signaling pathway of several hormones, including PTH. Mutations in GNAS lead to impaired signaling and resistance to PTH, resulting in the biochemical abnormalities seen in pseudohypoparathyroidism.

Diagnosis

Diagnosis of AHO is based on clinical features, biochemical tests, and genetic testing. Key diagnostic criteria include:

• Biochemical Tests: Elevated levels of PTH with low calcium and high phosphate levels in the blood.
• Genetic Testing: Identification of mutations in the GNAS gene.

Treatment

Management of Albright Hereditary Osteodystrophy focuses on addressing the symptoms and biochemical abnormalities. Treatment options may include:

• Calcium and Vitamin D Supplementation: To manage hypocalcemia.
• Hormone Replacement Therapy: In some cases, to address hormone resistance.
• Surgical Intervention: For removal of subcutaneous calcifications if they cause discomfort or functional impairment.

Prognosis

The prognosis for individuals with Albright Hereditary Osteodystrophy varies depending on the severity of the condition and the effectiveness of treatment. With appropriate management, many individuals can lead relatively normal lives.

Also see

• Pseudohypoparathyroidism
• Parathyroid hormone
• GNAS complex locus
• Endocrinology