HDR is an acronym for hypoparathyroidism,
deafness, and renal dysplasia. DiGeorge-like syndrome characterized by
hypoparathyroidism, heart defects, immune deficiency, deafness, and renal
malformations caused by a haplo-insufficiency of the zinc-finger
transcription factor GATA3.
Baraka Syndrome; Nephrosis Nerve Deafness
Approximately 40 cases described in the literature
Autosomal dominant disorder caused by
mutations in the GATA3 gene on chromosome 10. Gene map location is 10p15.
The GATA3 gene is part of the family of
zinc-finger transcription factors; it is involved in vertebrate embryonic
development and in the development of the parathyroids, inner ear, and
Diagnosis is based on clinical and laboratory stigmata,
genetic testing, and family history.
The typical triad of HDR—sensorineural
deafness, hypocalcemia and/or hypoparathyroidism, and nephropathy—is
present in almost all patients. The manifestation of renal involvement is
variable and may range from vesicoureteral reflux to kidney aplasia.
Developmental delay, seizure disorder, and a high incidence of cerebral
infarcts have been described. Mild dysmorphic features may be present and
may include hypertelorism, flat nose, proptosis, high arched palate,
micrognathia, and limb anomalies.
Clinical examination with emphasis
on facial malformations and routine blood work, including complete blood
count, electrolytes, calcium, glucose, and kidney function test are
required. Hematologic or biochemical disturbances, especially hypocalcemia,
must be corrected prior to anesthesia. A complete medical history and
current medication, for example, antiseizure drugs with the potential for
drug interactions with anesthetic agents, must be documented. Anxiolysis is
particularly important with deafness and mental retardation.
Calcium levels should be monitored
regularly during blood transfusions or albumin infusions and corrected if
necessary. Tracheal extubation can be difficult in patients with severe
mental retardation because of the presence of chronic lung disease from
recurrent aspirations and reduced ability to cough. In these more severely
affected patients, the potential for postoperative mechanical ventilation
must be considered and intensive care admission planned ahead.
Negative inotropic effects of
anesthetic agents and response to neuromuscular blockade might be enhanced
in the presence of hypocalcemia. Drugs with predominantly renal elimination
should be used with caution in the presence of impaired kidney function.
Consider antibioprophylaxis because these patients have potentially severe
impairment of immune function.
DiGeorge Syndrome: Developmental field defect with facial
dysmorphism, congenital heart defect, hypocalcemia, hypoparathyroidism,
thymus hypoplasia, and increased susceptibility to infections. The hallmarks
include conotruncal absence or hypoplasia of thymus and parathyroid glands.
Mostly caused by a microdeletion in chromosome 22q11.2.
Velocardiofacial Syndrome: Unusual face syndrome. Seems
associated with a defect of chromosome 22 (deletion 22q11). The most common
features are cleft palate, congenital heart defects (interrupted aortic
arch, truncus arteriosus, tetralogy of Fallot with pulmonary atresia, absent
pulmonary valve syndrome, simple tetralogy of Fallot, ventriculoseptal
defect, and d-transposition of the great arteries),
hypoparathyroidism, seizures, muscular hypotonia, short stature, and
scoliosis. The incidence of ...