Case of Two Sisters Highlights Rare Heart Problems in Sanfilippo
Sanfilippo syndrome affected the hearts of two sisters with the rare genetic disorder, without causing any of its more typical neurological symptoms, according to a case report.
The case highlights the importance of recognizing — and treating — such rare non-neuronal manifestations of the disease, the researchers said.
“Early recognition and cardiac transplantation are essential for patients with cardiac involvement,” they wrote.
The report, “Sanfilippo syndrome type A: early cardiac involvement of two patients with cardiac manifestations,” was published in Cardiovascular Pathology.
A team of scientists in Canada described the case of two sisters who were diagnosed with Sanfilippo type A late in childhood — the first at age 15, and her younger sister at age 12. Diagnoses for both sisters were made based on tests that showed high levels of heparan sulfate in their urine, and reduced activity of the protein whose defect causes this type of Sanfilippo syndrome.
Sanfilippo type A typically manifests in early childhood, between ages 2 and 6. Moreover, it is usually characterized primarily by neurological symptoms like unusual behaviors and developmental delays.
In contrast to that usual disease course, neither of the sisters experienced any unusual neurological symptoms. Nor did they have other common signs of Sanfilippo, like unusual bodily features, vision problems, or liver damage.
Both sisters later in life — in their early 30s — experienced skeletal changes, which led each of them to get total hip replacement surgery (hip arthroplasty).
Shortly after the surgery, the elder sister developed severe tricuspid valve regurgitation. In this form of heart disease, the valve between the two chambers on the right side of the heart — the right ventricle and right atrium — doesn’t close correctly.
By the age of 45, the older sister was in heart failure, and she underwent a heart transplant. She is currently alive and well, the researchers report.
The younger sister also developed heart failure, accompanied by problems with the tricuspid valve, in her 40s. She also had unusual heart rhythms, for which a defibrillator was implanted.
The patient was being assessed for a potential heart transplant when her condition worsened, with kidney failure and other complications, ultimately leading to her death.
Both sisters’ hearts were taken for laboratory assessments. The researchers noted that both patients had dilated cardiomyopathy, in which the heart chambers enlarge and lose the ability to contract. Additionally, the disease in both patients was found to mainly affect the right side of the heart, which is responsible for pumping blood to the lungs to pick up oxygen.
“Cardiovascular abnormalities among patients with [Sanfilippo syndrome] have been rarely reported,” the researchers wrote.
“In our opinion, physicians evaluating adults should always consider adult presentations of storage conditions,” the team concluded, adding, “it is also essential to recognize the extra-neuronal forms of [Sanfilippo type A], which might be mainly limited to the heart.”