Autosomal recessive cystinuria caused by genome-wide paternal uniparental isodisomy in a patient with Beckwith-Wiedemann syndrome.

[cystinuria]

Approximately 20 % of Beckwith-Wiedemann syndrome (BWS ) cases are caused by mosaic paternal uniparental disomy of chromosome 1 1 (pUPD 11 ). Although pUPD 11 is usually limited to the short arm of chromosome 11 , a small minority of BWS cases show genome-wide mosaic pUPD (GWpUPD ). These patients show variable clinical features depending on mosaic ratio , imprinting status of other chromosomes , and paternally inherited recessive mutations . To date , there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation . Here , we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria . Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC 7 A 9 . This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism . Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD .