D. J. Reijngoud

A patient with lethal cardiomyopathy and a carnitine-acylcarnitine translocase deficiency

In the last few years, increasing attention has been paid to the diagnosis of defects in mitochondrial fatty acid beta-oxidation in man (Stanley 1987). Clinical diagnosis of these disorders is difficult, because affected patients are often free of symptoms between metabolic crises (Hale and Bennett 1992). A total of 13 inherited beta-oxidation defects have been described (Coates and Tanaka 1992). Among those 13 disorders there are four that affect the transport into mitochondria of long-chain fatty acids that are activated to their CoA esters. Defects have been described for the plasma-membrane carnitine transporter and carnitine palmitoyltransferase types 1 and 2 (CPT I and II). Recently three patients have been described with a carnitine- acylcarnitine translocase deficiency, a defect in the transfer of fatty acylcarnitines across the inner mitochondrial membrane in exchange for free carnitine (Pande et al 1993; Stanley et al 1992; Brivet et al 1994). In this short communication we describe what is to our knowledge the fourth case of a carnitine-acylcarnitine translocase deficiency.

Xanthinuria in a family of Cavalier King Charles spaniels

Xanthine calculi were found in a 7-month-old male Cavalier King Charles spaniel with urethral obstruction and renal insufficiency. Because the only two other reported cases of naturally occurring xanthine urolithiasis concerned a Cavalier King Charles and a King Charles spaniel the urine of the littermates and parents of the patient were also examined for xanthinuria. Semi-quantitative analysis revealed high urine concentrations of hypoxanthine and xanthine in the patient and his female littermate. Quantitative analysis by high-pressure liquid chromatography (HPLC) of the urine samples from the family of this Cavalier King Charles spaniel and nine control dogs revealed that hypoxanthine and xanthine excretion was 30 and 60 times higher in the affected patient and the female littermate than in the others dogs. The pattern of xanthinuria, which is caused by a deficiency of the enzyme xanthine oxidase, in the relation diagram of this family of Cavalier King Charles Spaniels was consistent with an autosomal recessive mode of inheritance.