Homozygous variegate porphyria: a compound heterozygote with novel mutations in the protoporphyrinogen oxidase gene.

Homozygous variegate porphyria results from mutations in both alleles of the protoporphyrinogen oxidase (PPOX) gene. Our patient, a 36-year-old woman, has severe cutaneous manifestations. Her clinical and biochemical features are similar to the few other reported cases, including onset before 18 months of age, photosensitivity, absence of acute porphyric attacks, and elevated erythrocyte protoporphyrin. Mutation analysis of the PPOX gene revealed an in-frame 12 bp insert (c. 657-658 ins AAGGCCAGCGCC) encoding lysine-alanine-serine-alanine (KASA), and a G to A transition at the splice donor site of exon 11 (IVS 11-1 G-->A). Neither of these mutations has been reported previously. Our patient's mother has the splice site mutation and has had acute porphyric episodes. A maternal first cousin has the same mutation but no clinical manifestations. The medical and family history of our patient's father is uncertain.

Tissue oxygenation, venous ulcers and fibrin cuffs.

Skin oxygen tension (TcPO2) was measured at 43 degrees C on patients (n = 27) with venous ulcers. Measurements were made at ulcer edge and proximally on the same limb for control. Similar measurements were also made on healthy volunteers (n = 14) in the medial aspects of the distal third of the legs. TcPO2 at ulcer edge was significantly lower (P = 0.001) than control values which in turn were lower than that measured on healthy volunteers. TcPO2 reflects skin nutrition. While low TcPO2 at ulcer edges might be the result of pericapillary barriers to oxygen transport, the control values measured on apparently normal skin suggest the need for further studies.

Methylprednisolone pulses and urine electrolyte excretion.

The mineralocorticoid activity of methylprednisolone pulses was assessed by measurement of urine electrolyte excretion prior to and during alternate day pulsing in patients with skin or joint disease. Two groups were studied: the first receiving pulses, but no other steroid; the second having taken oral prednisolone prior to and during pulsing. Urine sodium excretion in 24 hr urine specimens from both groups was suppressed, with no rebound between pulses, but a gradual "escape" occurred from the effects of continued pulsing. Four hour urine collections demonstrated suppression of urinary sodium excretion for up to 32 hr after pulsing with gradual recovery. The peak recovery in sodium excretion coincided with the subsequent pulse and was insufficient to compensate for the preceding sodium retention. Alternate day pulsing does not, therefore, reduce the risk of sodium retention from large doses of methylprednisolone.

Severe atypical molluscum contagiosum infection in an immunocompromised host.

A case of severe molluscum contagiosum in a patient with treated thymoma is described. This unusual complication of immunosuppression is discussed and the literature on the subject reviewed.