On genetic testing, the girl was found to have a variant of the IFITm5 gene, which can cause osteogenesis imperfecta V, a disease in which bones are susceptible to easy fracture.
She was managed with zoledronate, calcium and vitamin D supplements.
Dr. Nameirakpam said the disease can mimic inflammatory arthritis, so caution is needed.
“So don’t go into your knee-jerk reflex of starting DMARDs [disease-modifying anti-rheumatic drugs] when we have some arthritis or arthritis-like picture,” he said.
19-Year-Old Male with a Worsening Headache
Rasha Elrefai, MD, a pediatric rheumatology fellow at Baylor College of Medicine, Houston, discussed a 19-year-old male with a worsening headache and vision and memory issues whose health challenges began early in life. He had Evans syndrome and recurrent infections at age 2; erythema nodosum and necrotizing granuloma on lymph node biopsy at age 3; enteritis, colitis, immune dysregulation and T cell lymphopenia at age 15; and panuveitis and bilateral cataracts at age 17.
A physical exam showed short stature, flexion deformities in both hands, an eczematous rash along the elbows and a right-sided visual field deficit. His inflammatory markers were elevated, with mild leukocytosis, as well as lymphopenia and thrombocytopenia.
A brain MRI showed left posterior circulation artery infarction, which was concerning for stroke. A CT angiography of the head showed chronic injury with encephalomalacia in the posterior inferior left parietal lobe.
He was positive for antiphospholipid antibodies and began to have clinical seizure episodes, and he was given triple antiepileptic therapy, Dr. Elrefai said.
After a rheumatology consult, hydroxychloroquine was started and his mycophenolate mofetil dosing was optimized.
He was found to have immunodeficiency 71 with inflammatory disease and congenital thrombocytopenia (IMD-71), a rare disorder caused by a mutation in the ARPC1B gene, which is critical for regulating the actin cytoskeleton in immune cells. Deficiency of this gene leads to impaired T cell and B cell function, Dr. Elrefai said. Hematopoietic stem cell transplant is considered feasible and effective for the condition, she said.
She said the disorder can initially resemble systemic lupus erythematosus.
“Molecular diagnostics,” Dr. Elrefai said, “are crucial for distinguishing monogenic immune dysregulation disorders from acquired or idiopathic autoimmune conditions, fundamentally altering treatment approaches.”
Thomas R. Collins is a freelance medical writer based in Florida.
References
- Conticini E, d’Alessandro M, Al Khayyat SG, et al. Inflammatory muscle involvement in systemic vasculitis: A systematic review. Autoimmun Rev. 2022 Mar;21(3):103029.
- Lacou M, Leroy M, Lan NL, et al. Muscle biopsy in anti-neutrophil cytoplasmic antibody-associated vasculitis: Diagnostic yield depends on anti-neutrophil cytoplasmic antibody type, sex and neutrophil count. Rheumatology (Oxford). 2021 Feb 1;60(2):699–707.
