Lysinuric protein intolerance in a family of Mexican ancestry with a novel SLC7A7 gene deletion. Case report and review of the literature

Abstract

Lysinuric protein intolerance (LPI) is a rare autosomal recessive disorder caused by mutations in the SLC7A7 located on the chromosome 14q11.2. LPI is most prevalent in Finland (1:50,000), Northern Japan (1:60,000) and Italy. Cases have also been reported in Spain and the United States. Here we report two siblings of Mexican descent. The older child was diagnosed at the age of three with severe chronic respiratory insufficiency leading to her demise. In contrast, the younger child was diagnosed soon after birth and dietary therapy has led to a stable life. Genetic analysis revealed a previously unreported deletion in the SLC7A7 gene. Additional research is needed to clarify the role of lysine in the pathophysiology of pulmonary proteinosis and herpes infections.

Keywords: 14q11.2; Lysinuric; SLC7A7.

Fig. 1

HRCT of lungs, patient 1.

Fig. 2

40 × H&E of liver with focal glycogenosis (left) and lung with alveolar proteinosis (right). The liver biopsy contains a few clusters of hepatocytes with clear waxy cytoplasm (left arrow). The lung biopsy showed alveolar proteinaceous material (stars), septal thickening, type II pneumocyte hyperplasia and chronic inflammation. Cholesterol granulomas (right arrow) were also noted in many alveolar spaces.