To the Editor,

Glycogen storage disease type II, or Pompe disease, also called acid maltase deficiency, is a rare disease affecting lysosomal storage which is characterised by the accumulation of glycogen, mainly in muscle tissue. It is a hereditary autosomal recessive disorder with a deficiency of lysosomal acid α-glucosidase enzyme activity. The two most frequent subtypes of Pompe disease are the infantile and the late onset forms. The infantile form is the most serious and is characterised by cardiomegaly, general muscle weakness, hypotonia, hepatomegaly and death due to respiratory failure before the age of one. The late onset form, also known as juvenile or adult form, appears after the age of one and is characterised by damage to skeletal muscles, which causes progressive muscle weakness and respiratory insufficiency1. A prevalence of 1:57,000 in the population is estimated in the late onset form. Before 2006, it was an incurable disease with merely palliative treatment, but the development of recombinant human α-glucosidase enzyme substitution therapy constitutes the first specific treatment2. This therapy has allowed the disease’s progression to be reduced and/or stopped.

We present the case of a 37 year-old, type 2 non-heart-beating donor with late onset Pompe disease being monitored by our hospital and receiving enzyme therapy treatment. The patient suddenly died at home and was transferred to our hospital as a possible organ donor. Death was certified on arrival at the intensive care unit, with the following biochemical data: normal renal function with serum creatinine level at 0.78 mg/dl and glomerular filtration rate, using MDRD-4, of 85.7 ml/min and altered hepatic profile (GPT [ALT] 150 U/l, GOT [AST] 130 U/l and GGT 160 U/l) already known. Given the rarity of this condition, it was doubted whether a patient with this type of systemic disease could be an organ donor. After reviewing the medical literature, we could verify that there was no information on the subject.

In order to obtain the necessary and useful information that would help us make the correct decision, we consulted the clinical guides on late onset Pompe disease and its systemic damage, deciding to accept the patient as a donor on the absence of data specifically contrary to donation. Although all organs were evaluated, only the kidneys could be used (the liver was rejected due to altered hepatic profile during preservation). The kidneys were transplanted to two recipients aged 27 and 45 without prior transplants. The first recipient was a 27 year-old male with chronic kidney disease (CKD) secondary to Alport syndrome on haemodialysis for three years; the second recipient was also a male with CKD secondary to a polycystic disease on haemodialysis for four years. Sequential immunosuppression with thymoglobulin, micophenolic acid and steroids and late introduction of tacrolimus were used in accordance with usual treatment of a non-heart-beating donor. In both cases there was delayed graft function, which is frequent in kidneys coming from a non-heart-beating donor, subsequently progressively recovering renal function. Neither recipient presented acute rejection immediately following transplant and 18 months after, both showed normal renal function, negative proteinuria and absence of hydroelectrolytic disorders.

Late onset Pompe disease is a multisystemic disorder that can have a wide range of clinical manifestations, including progressive muscle weakness, especially the muscles in the pelvic girdle, and respiratory symptoms, which are the principal cause of morbidity and mortality due mainly to diaphragmatic involvement and involvement of intercostals muscles3. Other serious complications are those arising from the presence of intracranial aneurysms, usually underdiagnosed and potentially fatal, and cardiac disturbances, such as Wolf-Parkinson-White syndrome, which has been described in some affected patients. Regarding renal disease associated with this condition, isolated cases of electrolytic disorders that mimic Gitelman syndrome have been described4, with histological findings in which the presence of glycogen deposits in distal tubules stand out. A case of nephrotic syndrome has also been reported in a pediatric patient as a complication of high doses of enzyme replacement therapy triggered by immune complex deposits5.

In conclusion, it is necessary to highlight that there are an increasing number of patients with rare diseases who, thanks to new therapies, have a longer life expectancy. The case described shows that the knowledge of these conditions can allow us to reflect on the suitability of these patients as a source of organ donors.

Conflicts of interest

The authors declare that they have no conflicts of interest related to the contents of this article.