CONTEXT: Goiter and deafness can be associated in some genetic syndromes, e.g. 
Pendred syndrome (PS) and resistance to thyroid hormone (RTH). PS is an 
autosomal recessive disorder characterized by goiter and sensorineural hearing 
impairment with an enlarged vestibular aqueduct bilaterally. RTH is an autosomal 
dominant condition of reduced tissue sensitivity to thyroid hormone in which 
goiter is very frequent and hearing loss occurs in about 20% of patients. 
OBJECTIVE, PATIENTS, AND DESIGN: The objective of this study was to identify the 
cause of goiter and deafness in two sisters born to healthy unrelated parents. 
We present their history, clinical presentation, and follow-up and report the 
results of molecular genetic investigations.
RESULTS: The elder sister had an elevated TSH level at newborn screening 
followed by subclinical hypothyroidism, childhood-onset goiter, and bilateral 
progressive sensorineural hearing impairment with enlarged vestibular aqueducts, 
consistent with a diagnosis of PS. Her younger sister had congenital goiter, 
elevated free T3 and free T4 concentrations with unsuppressed TSH, sinus 
tachycardia, and bilateral progressive sensorineural hearing impairment with 
enlarged vestibular aqueducts. This clinical presentation was consistent with a 
diagnosis of RTH, in which, however, inner ear malformations are uncommon. 
Interestingly, molecular genetic testing showed that, whereas the elder sister 
is affected by PS, the younger sister has both PS (due to compound heterozygous 
SLC26A4 mutations) and RTH (due to a novel de novo heterozygous THRB mutation).
CONCLUSIONS: This is the first report of the cooccurrence, in the same 
individual, of PS and RTH, two genetic syndromes both associated with goiter and 
hearing impairment.