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What

This syndrome has several names, the most commonly used is the name of Dr. Barakat, the first physician to describe it in 1977. Other names relate to the clinical symptoms present in affected persons. Barakat syndrome is a rare disorder causing low parathyroid hormone (hypoparathyroidism), deafness and kidney disease. The deafness found in children with this disorder is caused by abnormal inner ear structures and is described as sensorineural deafness.

Who

This disease is very rare, but appears to occur equally in males and females. Because it is so rare it is difficult to say if it is present in one ethnic group more than another. This disease often first appears in children during the first few months of life to early childhood.

Signs and Symptoms

Common signs and symptoms include;

• Hypoparathyroidism: Parathyroid hormone is produced by the parathyroid glands which are located in the neck. Having low parathyroid hormone levels result in low blood calcium and high phosphorus levels. This can lead to many different problems including; o dry and course skin o coarse, brittle and sparse hair o brittle nails o learning problems
  
• Sensorineural deafness: Children may have hearing loss in one or both ears. The hearing problem may then cause speech and communication problems.
• Renal disease: Children may have kidney problems that result in the decreased ability to produce urine.

Possible Causes

The disease is inherited in both an autosomal dominant and recessive manner. It is now thought that Barakat syndrome is sometimes caused by a genetic change (mutation) in a gene named GATA3. This gene is located on chromosome 10. The function of this gene is not completely understood, but it seems to be needed in the part of the ear named the cochlea and some parts of the central nervous system which would explain why children with this disorder are deaf.

Diagnosis

Children with Barakat syndrome have under-developed or missing parathyroid glands which result in a low level of parathyroid hormone. Low parathyroid hormone causes a low calcium level and a high phosphate level which can be detected on blood tests. Hearing tests might be performed to test for hearing loss. Intravenous urography (IVU), also known as intravenous pyleography (IVP), is an X-ray done to evaluate the urinary tract. An injection of contrast material containing iodine will be injected into the patient before the X-ray is taken, to show the pathway of urine from the kidneys to the bladder. Patients with Barakat syndrome might show small or irregular kidneys on IVU. Analysis of the urine is done to show the presence of protein or blood in the urine.

Treatment

1. Hypoparathyroidism: Calcium supplementation and vitamin D are used to treat abnormally low levels of calcium. 2. Sensorineural deafness: Hearing loss can progress to total deafness in the involved ear(s) and is irreversible. Surgery to place a hearing device called a cochlear implant may be possible. This device uses electrical stimulation to provide hearing and may improve language and communication skills. 3. Renal disease: Dialysis or kidney transplant may be necessary to treat kidneys that increasingly fail to function properly.

Prognosis

Because this is a very rare disease the prognosis of the disease is not well known. The kidney disease can be the most serious and difficult part of this syndrome to treat.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.

Weblinks

Hypoparathyroidism Association
Good website with links and a chat forum for patients with hypoparathyroidism and their families.

About.com
This website has a news letter, FAQs on deafness and hearing impairment, as well as articles on the deaf community and sign language.

National kidney foundation
Great, comprehensive website about all kidney diseases, including pediatrics ones. Also has information on hemodialysis and kidney transplants.

Google Search for Barakat Syndrome

References and Sources

Hasegawa T, et al (1997). HDR syndrome (hypoparathyroidism, sensorineural deafness, renal dysplasia) associated with del(10)(p13). Am. J. Med. Genet. 73: 416-418. Muroya K, et al (2001). GATA3 abnormalities and the phenotypic spectrum of HDR syndrome. J. Med. Genet. 38: 374-380. Van Esch H, et al (2000). GATA3 haplo-insufficiency causes human HDR syndrome. Nature 406: 419-422.