The importance of considering monogenic causes of autoimmunity: A somatic mutation in KRAS causing pediatric Rosai-Dorfman syndrome and systemic lupus erythematosus.

OBJECTIVES: Clinicians need to be aware of the growing list of defined monogenic etiologies of autoimmune diseases. This is particularly relevant when evaluating children, as these rare monogenic forms of autoimmunity tend to present very early in life. METHODS AND RESULTS: By harnessing the transformative power of next generation sequencing, we made the unifying diagnosis of RAS-associated autoimmune leukoproliferative disease (RALD), caused by the somatic gain-of-function p.G13C KRAS mutation, in a boy with the seemingly unrelated immune dysregulatory conditions of Rosai-Dorfman and systemic lupus erythematosus (SLE). CONCLUSIONS: This case expands our understanding of the clinical phenotypes associated with the extremely rare condition of RALD, and emphasizes the importance of always considering the possibility of a monogenic cause for autoimmunity, particularly when the disease manifestations begin early in life and do not follow a typical clinical course.

Use of propranolol in treating hemangiomas.

QUESTION: I see many children with infantile hemangiomas and have read about new therapeutic options such as propranolol. Is this medication effective and safe for treating hemangiomas in children? ANSWER: Most infantile hemangiomas resolve spontaneously without any need for therapy. In many case series, propranolol has been shown to be effective and safe in treating hemangiomas that cause complications. Further studies are required to determine the optimal dose and duration of propranolol treatment for problematic hemangiomas.

Mutations involved in Aicardi-Goutières syndrome implicate SAMHD1 as regulator of the innate immune response.

Aicardi-Goutières syndrome is a mendelian mimic of congenital infection and also shows overlap with systemic lupus erythematosus at both a clinical and biochemical level. The recent identification of mutations in TREX1 and genes encoding the RNASEH2 complex and studies of the function of TREX1 in DNA metabolism have defined a previously unknown mechanism for the initiation of autoimmunity by interferon-stimulatory nucleic acid. Here we describe mutations in SAMHD1 as the cause of AGS at the AGS5 locus and present data to show that SAMHD1 may act as a negative regulator of the cell-intrinsic antiviral response.

Cystic bone lesions in a boy with Darier disease: a magnetic resonance imaging assessment.

We describe asymptomatic bone cysts in the right humerus of a 17-year-old boy with Darier disease. The cysts were found when a radiographic skeletal survey was performed to monitor for adverse effects of oral retinoid therapy. Magnetic resonance imaging was used to confirm that the lesions were cystic and to delineate their extent. The literature was reviewed for previous reports of this association.

Treatment of cystic lymphatic vascular malformations with OK-432 sclerotherapy.

BACKGROUND: Cystic lymphatic vascular malformations are benign lesions that can cause disfigurement and functional impairment. Complete surgical resection is often difficult, and clinical recurrence is common. Sclerotherapy has been used as an alternative to excision. OK-432 is a lyophilized mixture of Streptococcus pyogenes and benzylpenicillin which, when injected into a lesion, has shown significant ability to reduce its size or obliterate it completely. METHODS: The authors report a series of 12 patients treated in this fashion at the Vascular Anomalies Clinic, British Columbia Children's Hospital, between 1999 and 2004. All patients underwent imaging of the lesion: 10 had magnetic resonance imaging, one had a computed tomographic scan, and one had ultrasound examination. Six patients had macrocystic malformations (cysts > or = 2 cm) and six had microcystic or combined lymphaticovenous malformations. Patients were treated with intralesional injection of OK-432. The position of the injection was confirmed by angiography and/or ultrasound in 10 cases. Response to treatment was assessed clinically. RESULTS: All patients with macrocystic malformations had complete resolution or good response to treatment. None required any additional treatment. In contrast, those with microcystic or combined malformations responded poorly. All of these patients underwent subsequent excision without adverse consequences. The size and location of the lesion did not correlate with response to treatment. Seventy-five percent of patients experienced pyrexia. Local swelling is an expected phenomenon and must be anticipated, particularly for lesions near the airway. CONCLUSIONS: OK-432 is an excellent treatment for patients with macrocystic lymphatic malformations. However, it is ineffective for microcystic lesions.

Cerebellar and cerebral atrophy in trichothiodystrophy.

Trichothiodystrophy is a rare neuroectodermal disorder of autosomal recessive inheritance that is characterized by brittle hair, nail dysplasia, ichthyosis, mental retardation, and gonadal failure. We describe a female patient whose cranial MRI revealed almost total lack of myelination in the supratentorial white matter, which is similar to the previously described cases. In addition, there was progressive cerebellar and cerebral atrophy, which has not been well documented in association with trichothiodystrophy.

A pruritic linear urticarial rash, fever, and systemic inflammatory disease in five adolescents: adult-onset still disease or systemic juvenile idiopathic arthritis sine arthritis?

The characteristic rash of systemic juvenile idiopathic arthritis is a transient erythematous eruption associated with a quotidian spiking fever. Usually asymptomatic, it can be pruritic, with dermatographism at sites of scratching or pressure. An illness similar to this entity in adults is designated adult-onset Still disease. The relationship between the pediatric and adult disease is uncertain and differences in case definition have evolved. Specifically, a sustained arthritis for at least 6 weeks is required for a diagnosis of systemic juvenile idiopathic arthritis, whereas transient arthritis and arthralgia are accepted criteria in adult-onset Still disease. We describe five patients less than 16 years of age who presented with an acute illness characterized by fever and a distinctive skin eruption. Intense pruritus and linear erythematous lesions flared with a spiking fever, usually in the late afternoon and evening. Periorbital edema/erythema and nonlinear urticarial lesions were also seen. Two children had splinter hemorrhages of the nail beds and one girl developed a fixed, scaling, pigmented, linear eruption. Severe malaise, myalgia, arthralgia, and leukocytosis were present in every patient. Other systemic manifestations included sore throat, transient arthritis, abdominal pain, lymphadenopathy, hepatomegaly, splenomegaly, hyperferritinemia, and hepatic dysfunction. No patient had a sustained arthritis. The course of the disease was variable. One patient, diagnosed with macrophage activation syndrome, recovered on oral naproxen. Two patients responded to systemic corticosteroid therapy. One girl developed status epilepticus and died from aspiration and asphyxia. A boy with severe hepatitis developed renal failure and thrombotic thrombocytopenic purpura and was treated with plasmapheresis, dialysis, and systemic corticosteroids; he had recurrent episodes of rash and fever into adult life. These children did not fulfill the case definition of systemic juvenile idiopathic arthritis because they lacked a persistent arthritis. Adolescent and adult patients with the same clinical and laboratory findings are described under the rubric of adult-onset Still disease. Recognition of the distinctive urticarial skin eruption and spiking fever is important in the diagnosis of a disease with severe morbidity and potentially life-threatening complications.

Detection and genotyping of varicella-zoster virus by TaqMan allelic discrimination real-time PCR.

A proportion of individuals vaccinated with live attenuated Oka varicella-zoster virus (VZV) vaccine subsequently develop attenuated chicken pox and/or herpes zoster. To determine whether postvaccination varicella infections are caused by vaccine or wild-type virus, a simple method for distinguishing the vaccine strain from wild-type virus is required. We have developed a TaqMan real-time PCR assay to detect and differentiate wild-type virus from Oka vaccine strains of VZV. The assay utilized two fluorogenic, minor groove binding probes targeted to a single nucleotide polymorphism in open reading frame 62 that distinguishes the Oka vaccine from wild-type strains. VZV DNA could be genotyped and quantified within minutes of thermocycling completion due to real-time monitoring of PCR product formation and allelic discrimination analysis. The allelic discrimination assay was performed in parallel with two standard PCR-restriction fragment length polymorphism (RFLP) methods on 136 clinical and laboratory VZV strains from Canada, Australia, and Japan. The TaqMan assay exhibited a genotyping accuracy of 100% and, when compared to both PCR-RFLP methods, was 100 times more sensitive. In addition, the method was technically simpler and more rapid. The TaqMan assay also allows for high-throughput genotyping, making it ideal for epidemiologic study of the live attenuated varicella vaccine.

Central nervous system involvement in neonatal lupus erythematosus.

Computerized tomography (CT) of the brain was performed in 10 of 11 consecutive infants with neonatal lupus erythematosus (NLE) (five boys and six girls). Ten of the 11 infants had brain neurosonography. Nine of 10 infants had abnormal CT scans. There was diffuse, markedly reduced attenuation of the cerebral white matter in four infants studied in the first week of life, and also in an infant 5 weeks of age. Patchy reduced subcortical white matter attenuation was observed in another 5-week-old infant. Basal ganglia calcifications were present in two infants at 2 months of age, one of whom also had mild ventriculomegaly. A patient with macrocephaly studied at 4 months of age had enlarged ventricles and subarachnoid spaces consistent with benign macrocephaly of infancy. Cerebral ultrasound examination was abnormal in all five infants studied in the first week of life and in one infant at 2 months of age. Findings included subependymal cysts (4), echogenic white matter (3), and echogenic lenticulostriate vessels (3). Apart from one case of macrocephaly, there was no clinical evidence of neurologic disease and the subsequent development of these infants has been normal. Subclinical central nervous system (CNS) disease in NLE is likely to be a transient phenomenon that resolves as maternal antibodies are cleared from the infant's circulation. It is important to be aware of these neuroimaging abnormalities to avoid misdiagnosis of congenital viral infection in a newborn with multisystem NLE. The potential for neurologic sequelae is uncertain.