1 Department of Renal Medicine, Leeds General Infirmary, Leeds, UK, 2 Department of Renal Medicine and 3 Department of Pathology, St James's University Hospital, Leeds, UK
Keywords: focal segmental glomerulosclerosis; nail-patella syndrome; nephrotic syndrome
Case
A 35-year-old man with hypertension and nephrotic-range proteinuria (4.5 g/24 h) was referred for nephrological assessment. There was no past medical history of relevance other than a congenital fixed deformity of the right elbow, which the patient attributed to maternal use of thalidomide during pregnancy. Clinical examination was unremarkable except for the detection of dystrophic changes involving several fingernails (Figure 1) and small patellae. The serum creatinine was normal. An autoimmune screen was negative, and serum complement levels were within the normal range. A renal biopsy was performed. This showed focal segmental glomerulosclerosis. Electron microscopy revealed irregular thickening of the glomerular basement membrane with areas of rarefaction, giving rise to a pathognomonic moth-eaten appearance (Figure 2
). An X-ray of the right elbow showed hypoplasia of the head of the radius (Figure 3
). X-rays of both knees confirmed rudimentary patellae (Figure 4
). On further questioning, it was established that a first-degree relative had nail abnormalities that were similar to the propositus.
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Discussion
The nail-patella syndrome (NPS) is an autosomal dominant disorder with variable expression. The underlying genetic defect has only recently been localized to LMX1B gene on chromosome 9 [1,2]. NPS is characterized by the tetrad of dysplastic nails, hypoplastic or absent patella, dislocation of the radial head and iliac horns. In addition, renal and ocular abnormalities have been reported [3]. Clinical studies have shown that progression to end-stage renal failure occurs in approximately one third of individuals, usually in early adulthood but occasionally in childhood or late adulthood [4]. Renal transplantation is generally successful, although there is a theoretical risk of Goodpasture's syndrome occurring in the allograft. It is important to offer family members nephrological review.
Acknowledgments
JS is supported by the Yorkshine Kidney Research Fund.
Notes
Correspondence and offprint requests to: Dr John Stoves, Department of Renal Medicine, St James's University Hospital, Leeds LS9 7TF, UK. Email: johnstoves{at}compuserve.com
References