Translational science of rare diseases最新文献

Lysosomes are cytoplasmic organelles that contain a variety of different hydrolases. A genetic deficiency in the enzymatic activity of one of these hydrolases will lead to the accumulation of the material meant for lysosomal degradation. Examples include glycogen in the case of Pompe disease, glycosaminoglycans in the case of the mucopolysaccharidoses, glycoproteins in the cases of the oligosaccharidoses, and sphingolipids in the cases of Niemann-Pick disease types A and B, Gaucher disease, Tay-Sachs disease, Krabbe disease, and metachromatic leukodystrophy. Sometimes, the lysosomal storage can be caused not by the enzymatic deficiency of one of the hydrolases, but by the deficiency of an activator protein, as occurs in the AB variant of GM2 gangliosidosis. Still other times, the accumulated lysosomal material results from failed egress of a small molecule as a consequence of a deficient transporter, as in cystinosis or Salla disease. In the last couple of decades, enzyme replacement therapy has become available for a number of lysosomal storage diseases. Examples include imiglucerase, taliglucerase and velaglucerase for Gaucher disease, laronidase for Hurler disease, idursulfase for Hunter disease, elosulfase for Morquio disease, galsulfase for Maroteaux-Lamy disease, alglucosidase alfa for Pompe disease, and agalsidase alfa and beta for Fabry disease. In addition, substrate reduction therapy has been approved for certain disorders, such as eliglustat for Gaucher disease. The advent of treatment options for some of these disorders has led to newborn screening pilot studies, and ultimately to the addition of Pompe disease and Hurler disease to the Recommended Uniform Screening Panel (RUSP) in 2015 and 2016, respectively.

Objective: To investigate daily function among individuals with Wolfram Syndrome (WFS) and examine whether any limitations are related to disease-related symptoms.

Methods: WFS (n = 31), Type 1 diabetic (T1DM; n = 25), and healthy control (HC; n = 29) participants completed the Pediatric Quality of Life Questionnaire (PEDSQL) Self and Parent Report. PEDSQL domain scores were compared among these groups and between WFS patients with and without specific disease-related symptoms. Relationships between PEDSQL scores and symptom severity as assessed by the Wolfram Unified Rating Scale (WURS) Physical Scale were also examined.

Results: Across most domains, the WFS group had lower PEDSQL Self and Parent Report scores than the T1DM and HC groups. WFS participants with urinary, sleep, and temperature regulation problems had lower PEDSQL scores than those without. The WURS Physical Scale correlated with Self and Parent Report PEDSQL domains. WFS group Self and Parent Reports correlated with each other.

Conclusions: The WFS group reported lower daily function compared to T1DM and HC groups. Within WFS, worse symptom severity and the specific symptoms of sleep, temperature regulation, and urinary problems were associated with poorer daily function. These findings provide rationale for an increased emphasis on identifying, treating and understanding these less well-known symptoms of WFS.

The three essential branched-chain amino acids (BCAAs), leucine, isoleucine and valine, share the first enzymatic steps in their metabolic pathways, including a reversible transamination followed by an irreversible oxidative decarboxylation to coenzyme-A derivatives. The respective oxidative pathways subsequently diverge and at the final steps yield acetyl- and/or propionyl-CoA that enter the Krebs cycle. Many disorders in these pathways are diagnosed through expanded newborn screening by tandem mass spectrometry. Maple syrup urine disease (MSUD) is the only disorder of the group that is associated with elevated body fluid levels of the BCAAs. Due to the irreversible oxidative decarboxylation step distal enzymatic blocks in the pathways do not result in the accumulation of amino acids, but rather to CoA-activated small carboxylic acids identified by gas chromatography mass spectrometry analysis of urine and are therefore classified as organic acidurias. Disorders in these pathways can present with a neonatal onset severe-, or chronic intermittent- or progressive forms. Metabolic instability and increased morbidity and mortality are shared between inborn errors in the BCAA pathways, while treatment options remain limited, comprised mainly of dietary management and in some cases solid organ transplantation.