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Biomedical subjects

S Refetoff

Publications and source records attributed to S Refetoff.

At least 271 records · Page 15Linked to original sources
PubMed1969

Genetic polymorphism of rhesus thyroxine-binding prealbumin: evidence for tetrameric structure in primates.

Polymorphism in primate thyroxine-binding prealbumin was investigated with agarose gel electrophoresis at pH 8.6. In the rhesus monkey (Macaca mulatta), three forms of this protein were found in random sera: a single rapidly migrating band similar to that in human and other primate sera, a single slowly migrating band cathodal to rhesus albumin, and a five-banded form, the most rapid and slowest bands of which corresponded to the other two forms. The frequencies of occurrence of these three forms were consistent with the hypotheses that rhesus prealbumin is under the control of two codominant autosomal alleles, PA(F) and PA(S), and that the protein occurs naturally in serum as a tetramer composed of similar subunits.It was possible, by simple mixing in vitro, to produce five-banded prealbumin patterns from rhesus PA SS serum and rhesus PA FF serum, M. arctoides serum, P. hamadryas serum, and human serum. Thyroxine was bound by all the hybrid molecules produced in this fashion.

Alleles↗
PubMedDate not supplied

A case of Resistance to Thyroid Hormone without mutation in the thyroid hormone receptor beta.

BACKGROUND: Resistance to Thyroid Hormone (RTH) is a condition caused by tissue hyposensitivity to the effects of circulating thyroid hormone, and may be misdiagnosed as hyperthyroidism. AIMS: We report the first case of RTH in an Irish patient highlighting the clinical features and the pathophysiological mechanism underlying the characteristic laboratory abnormalities found in the condition. METHODS: We describe an isolated case of RTH initially misdiagnosed as hyperthyroidism, and detail the investigations which ultimately led to the correct diagnosis. Genetic screening of the thyroid hormone receptor beta gene was performed. RESULTS: Thyroid function tests including T3 suppression test and TRH-stimulation test suggested a diagnosis of RTH. Genetic testing failed to demonstrate a mutation in the thyroid hormone receptor. CONCLUSION: RTH is a rare inherited condition that may be misdiagnosed as hyperthyroidism. The case we describe most likely results from a de novo mutation in an as yet undiscovered gene. RTH should be considered in patients with elevated thyroid hormone levels and normal TSH so that unnecessary and potentially harmful treatment can be avoided.

Adult↗
PubMedDate not supplied

Inherited X chromosome linked thyroxine-binding globulin (TBG) deficiency in a homozygous female.

Of the 37 families with TBG deficiency so far described, 31 were shown to be compatible with X chromosome linked mode of inheritance, and in 5 of the remaining 6 this mode of transmission was suspected. Difficulties in proving X chromosome linkage in some families was usually due to the inability to identify the heterozygous female carriers when affected males were only partially TBG deficient. This work describes a new family with inherited TBG deficiency which on first glance showed inconsistencies with X chromosome linked inheritance. More specifically, there was an apparent male to male transmission of the trait and the presentation in one female of low TBG, phenotypically indistinguishable from the affected males. Studies on three generations identified TBG deficiency on both the maternal and paternal branches of the family. We were thus able to prove that the affected male inherited the trait from his heterozygous mother, rather than from his father, and that the female with more severe TBG deficiency was homozygous for the trait through acquisition of a defective X chromosome from both mother and father. The latter explained her phenotype presentation indistinguishable from that in affected hemizygous males. Thus, unless proven otherwise, all inherited TBG abnormalities in man appear to be X chromosome linked. Because of the relatively common prevalence of inherited TBG defects, marriages among such individuals are expected to give rise to a progeny with an unusual phenotypic presentation. All members of the family were clinically euthyroid and affected members showed a normal TSH response to TRH.

Adolescent↗
PubMedDate not supplied

Multiple complications of propylthiouracil treatment: granulocytopenia, eosinophilia, skin reaction and hepatitis with lymphocyte sensitization.

An association of granulocytopenia, eosinophilia, skin reaction and hepatitis during propylthiouracil (PTU) therapy for thyrotoxicosis in a 47 year old black female is reported. Clinical and biochemical abnormalities disappeared soon after discontinuation of PTU. That the drug was directly responsible for the observed complications is suggested by the clinical course and by in vitro lymphocyte transformation studies. The latter revealed sensitization to PTU during the acute phase of the disease, which was greatly reduced 5 weeks after discontinuation of the drug and was completely absent after 5 months.

Agranulocytosis↗
PubMedDate not supplied

The syndrome of resistance to thyroid hormone, misdiagnosed and treated as thyrotoxicosis.

OBJECTIVE: To report two cases of resistance to thyroid hormone and to promote increased awareness of this syndrome, which is frequently misdiagnosed and incorrectly treated. METHODS: We describe a young woman and her father, both of whom were diagnosed at a younger age as having thyrotoxicosis and were treated with thyroidectomy and radioactive iodine. Both patients later proved to have resistance to thyroid hormone and required supraphysiologic doses of levothyroxine to normalize the thyroid-stimulating hormone (TSH) while remaining euthyroid. RESULTS: Laboratory evaluation revealed increased serum total thyroxine and triiodothyronine levels as well as normal to increased TSH levels. The free alpha sub-unit/TSH ratio was normal, and magnetic resonance imaging of the pituitary gland showed no tumor. Metabolic studies in the daughter, with use of graded doses of triiodothyronine, supported the diagnosis. CONCLUSION: Both patients shown to have resistance to thyroid hormone were misdiagnosed and inappropriately treated in the past. The resultant hypothyroidism has been difficult to treat, particularly in the father who has coronary artery disease.

Journal Article↗