Heart transplantation in two adolescents with Danon disease

Thrombotic microangiopathy following heart transplant in pediatric Danon disease

This case describes an uncommon acute complication of diffuse thrombotic angiopathy and associated aHUS/TTP in an 11-year-old girl with Danon disease who underwent orthotopic heart transplant. Shortly after transplant, despite an uncomplicated operative course, the patient developed severe kidney injury and progressive altered mental status, culminating in cerebral edema, brain herniation, and death. She had received a single dose of tacrolimus (FK506) and a single dose of antithymocyte globulin. Sources of progressive somnolence, including oversedation from impaired renal clearance of opiates, and severe myopathy as has been previously described in Danon disease, were ruled out, and the patient continued to decline. Initial brain CT scan early after transplant showed no signs of cerebral edema, but repeat CT indicated severe cerebral edema. Based on autopsy, diffuse thrombotic angiopathy, with signs of hemolytic anemia with schistocytes, was likely responsible for her deterioration in the broader condition of aHUS/TTP.

Pediatric waitlist and heart transplant outcomes in patients with syndromic anomalies

PURPOSE

We sought to determine whether the presence of a systemic SA with potential complicating factors affects waitlist and post-HT outcomes in pediatric patients.

METHODS

This is a single-center retrospective review of pediatric patients listed for HT between January 1, 2009, and July 1, 2018. Patients were selected based on the presence of any underlying syndromes, which included chromosomal anomalies, skeletal myopathies, connective tissue disorders, mitochondrial disease,and other systemic disorders. Waitlist and post-HT outcomes were compared to those without SA.

RESULTS

A total of 243 patients were listed for HT, of which 21 (9%) patients had associated SA. Of those, 16 (76%) survived to transplant, 3 (14%) died while on the waitlist, 1 (5%) improved and was removed from the waitlist, and 1 (5%) patient is currently listed. Waitlist survival was not different between those with/without an associated syndrome (P = 1.0). Among those who survived to HT, there was no difference in listing days (70 vs 90, P = .8), survival to hospital discharge [14 (93%) vs 150 (95%), P = .6], post-HT intubation days (2 vs 2 days, P = .6), or post-HT hospital length of stay (18 vs 18 days, P = .8). Overall survival during the study period post-HT was not different between groups (P = .8).

CONCLUSION

A SA was present in 9% of pediatric patients wait-listed for HT, but was not associated with an increased waitlist mortality or post-HT hospital morbidity or long-term survival. For several anomalies, HT is safe and feasible.

Three female patients with Danon disease presenting with predominant cardiac phenotype: a case series

Background

Danon disease is a rare X-linked multisystemic disorder that has primarily been described in male patients.

Case summary

We present three female patients with Danon disease with a predominantly cardiac phenotype in whom disease onset and expression was very different from that of male patients. Case 1 was first admitted for acute heart failure and then readmitted a few months later for cardiac shock, necessitating mechanical support, and heart transplantation. Case 2 had complex arrhythmias for which many antiarrhythmic drugs were tried with only limited success. Her disease accelerated after her first pregnancy, and she showed reduced left ventricular function and dilated cardiomyopathy. Case 3 was referred for near syncope and ablated for an accessory pathway; she had extensive left ventricular hypertrophy. In all three cases, a final diagnosis of Danon disease was only made after genetic testing that identified a causal variant in the lysosome-associated membrane protein 2 gene.

Discussion

Danon disease in female patients is a challenging diagnosis that may not be identified until genetic testing has been performed.