Undiagnosed thyroid disorder with PWS led to man’s Hoffman’s syndrome

Thyroid condition is more commonly seen in older adults who've gone untreated

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A person strains to lift a set of barbells.

The case of a young man with Prader-Willi syndrome who developed Hoffman’s syndrome, a condition marked by muscle weakness due to reduced thyroid gland function, was described in a recent report.

The patient’s muscle weakness was effectively treated with thyroid hormone replacement.

The study, “Hoffman’s syndrome as the presenting manifestation of non-primary hypothyroidism in a case of Prader-Willi Syndrome,” was published in Neurología.

The thyroid is a butterfly-shaped gland near the base of the throat. Its main job is to produce hormones that help regulate a range of important functions, including body temperature, heart rate, and metabolism. Thyroid abnormalities are common among people with Prader-Willi syndrome, affecting up to about a third of those with the condition.

The researchers described the case of a 20-year-old man from rural India who was evaluated at their center.

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As a baby, the man had difficulty feeding, but from when he was a toddler he had a voracious appetite that was difficult to satiate. He was delayed in reaching developmental milestones in childhood. On examination, he had notably underdeveloped secondary sex characteristics. These symptoms are common in Prader-Willi syndrome.

The young man also had notable muscle weakness. He was reported to have difficulty climbing stairs or rising from a seated position. Muscle weakness had begun subtly and had gotten progressively worse over six years.

A clinical evaluation showed muscle weakness was mainly proximal, meaning it most affected those close to the trunk. The man’s legs were most heavily affected. Notable muscle enlargement and swelling, as well as reduced reflexes, were also observed.

Diagnostic tests were run and genetic testing confirmed a diagnosis of Prader-Willi syndrome. Among the notable findings, the patient was found to have abnormally low levels of several thyroid hormones, indicative of hypothyroidism.

These low levels combined with the other symptoms suggested Hoffman’s syndrome, a specific manifestation of hypothyroidism marked by muscle weakness and enlargement. Hoffman’s syndrome is usually seen in older adults who’ve had unmanaged hypothyroidism for a long time, the researchers said.

The patient was started on levothyroxine, a medication approved for hypothyroidism that works to replace thyroid hormones. Dosing was gradually increased to 125 micrograms a day over three months, which led to marked reductions in some symptoms. The man’s muscle strength improved, his reflexes normalized, and the size of his muscles decreased to nearer normal levels.

Clinicians advised the man’s family to start him on growth hormone and testosterone replacement therapy, as well as continuous positive airway pressure (CPAP) therapy for sleep apnea. The family didn’t start these treatments, however, due to financial constraints.

Noting that Prader-Willi syndrome is known to often cause thyroid problems, the researchers said the most likely explanation for the man’s condition was that the underlying Prader-Willi led to thyroid impairment that went undiagnosed for many years, ultimately becoming severe enough to cause Hoffman’s syndrome.

Prader-Willi as the likely under cause of Hoffman’s syndrome “makes this case unique,” the researchers said.