Sunitinib-Induced Acute Interstitial Nephritis in a Thrombocytopenic Renal Cell Cancer Patient.

Sunitinib, a multitargeted tyrosine kinase inhibitor (TKI), is currently the standard of care for patients with metastatic renal cell carcinoma. Renal adverse events associated with sunitinib include proteinuria, renal insufficiency secondary to focal segmental glomerulosclerosis (FSGS), and thrombotic microangiopathy. We describe the second reported instance of biopsy-proven sunitinib-induced acute interstitial nephritis (AIN), in a challenging case complicated by thrombocytopenia. The case illustrates the importance of early diagnosis and intervention in ensuring long-term recovery from renal complications. Four other cases of AIN reported along with inhibition of the vascular endothelial growth factor (VEGF) by either TKI (sunitinib and sorafenib) or antibodies (bevacizumab) suggest a possible class effect. Given our experience, we recommend monitoring renal function with VEGF inhibition, and in the case of renal failure in the setting of an unclear diagnosis, we recommend prompt biopsy.

Serum neural cell adhesion molecule is hyposialylated in hereditary inclusion body myopathy.

Hereditary inclusion body myopathy (HIBM) is a young-adult onset autosomal recessive disorder caused by a hypomorphic rate limiting enzyme of sialic acid biosynthesis. The enzyme is UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, and is encoded by the GNE gene. HIBM causes slowly progressive muscle weakness and atrophy. Patients are typically diagnosed at 20-30 years of age, and most patients are incapacitated and wheelchair-confined by 30-50 years of age. Some sialic acid containing glycoproteins, including neural cell adhesion molecule (NCAM), are hyposialylated in HIBM muscle biopsy samples. We developed a method to allow detection of serum NCAM sialylation using Western blot, and tested serum samples from several patients and a HIBM mouse model. Preliminary results showed a clear difference in polysialylated and hyposialylated forms of NCAM extracted from serum, and showed NCAM is hyposialylated in HIBM serum samples. This initial finding may prove useful in reducing the need for serial muscle biopsies in HIBM treatment trials. Additional studies are underway to further validate this finding and to evaluate the specificity, reliability, and robustness of this potential serum biomarker for HIBM.

Wolman disease (LIPA p.G87V) genotype frequency in people of Iranian-Jewish ancestry.

Wolman disease (WD) is a rare inherited condition caused by lysosomal acid lipase (LAL) deficiency first described in Iranian-Jewish (IJ) children. Newborns with WD are healthy and active, but soon the infant develops symptoms of severe malnutrition in the first few months of life, and often dies before the age of 1 year. Harmful amounts of lipids accumulate in the spleen, liver, bone marrow, intestine, adrenal glands, and lymph nodes. Although worldwide incidence is estimated at 1/350,000 newborns, WD occurs at higher than expected frequency in the IJ community of the Los Angeles area. As a validation study, we analyzed 162 DNA specimens of IJ origin by automated sequencing. For LIPA p.G87V (ggc>gtc, alternative numbering p.G66V), a heterozygous frequency of 5/162 (3.086%) was discovered. Thus, we estimate that as high as 1 in 4200 newborns of IJ couples may be at risk. Additional studies are required to confirm and further validate the higher frequencies seen in our sample pool, and to determine if people of IJ and even possibly Middle Eastern descent are at a higher risk for WD.