This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Barakat syndrome, also known as HDR syndrome, is a rare, genetic syndrome characterized by hypoparathyroidism, sensorineural deafness, and renal (kidney) disease. However, specific symptoms and severity can vary. About 65% of people with Barakat syndrome have all three of these features, while the others have various combinations of these features. Some people with Barakat syndrome have one or more of these as well as additional features.
Hypoparathyroidism leads to low levels of calcium in the blood (hypocalcemia), which can cause symptoms such as muscle pain, muscle spasms, seizures, and rarely, cardiomyopathy. Hearing loss is the most consistent feature of Barakat syndrome. It is usually bilateral and can range from moderate to profound. The type of kidney disease present can vary from person to person. For example, some people with Barakat syndrome are born with structural kidney or urinary tract abnormalities (underdeveloped or abnormally-formed), while others may have functional abnormalities (such as nephrotic syndrome, hematuria, renal tubular acidosis, or chronic kidney disease). Various additional features have been reported in some people with Barakat syndrome such as polycystic ovaries, distinctive facial features, ischemic stroke, retinitis pigmentosa, intellectual disability, growth failure, congenital heart disease, and other birth defects.
Most cases of Barakat syndrome are caused by mutations in the GATA3 gene, or by a missing piece (deletion) of genetic material on chromosome 10 that includes the GATA3 gene. Inheritance is autosomal dominant. In some cases, the genetic cause is unknown. Barakat syndrome can be clinically diagnosed (without genetic testing) in a person with the complete triad of hypoparathyroidism, sensorineural deafness, and renal disease; or, in a person with two of these features who also has a positive family history. For those who have only deafness or renal disease, and for others who do not fit this criteria, genetic testing that identifies a GATA3 mutation is needed to confirm the diagnosis.
Treatment for Barakat syndrome depends on the symptoms present and the severity in each person. Hypocalcemia may be treated with oral calcium and calcitriol, intravenous calcium gluconate, or parathyroid hormone injection. Hearing loss may be treated with hearing amplification and/or cochlear implantation. Treatment of kidney disease depends on the abnormality present. Some minor abnormalities may not need to be treated while others may require medications, surgery, or kidney transplantation. The long-term outlook (prognosis) usually depends on the severity of kidney disease, and those with minor kidney problems have a normal life expectancy.
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