SAT580 Incidental Diagnosis Of Genetic Variant PTPN11 Noonan Syndrome With Multiple Lentigines, Sensorineural Hearing Loss And Rheumatoid Arthritis In Adult Female With Hashimoto’s Thyroiditis. Case Report

Disclosure: M.M. Eid: None. T. Zahra: None. J. Vargas-Jerez: None. Introduction: Hashimoto’s thyroiditis (HT, chronic lymphocytic thyroiditis, autoimmune thyroiditis) and Rheumatoid arthritis (RA) are autoimmune disorders, affect mainly females (1). Noonan syndrome with Multiple Lentigines (NSML, Leopard Syndrome) is a rare multigenetic autosomal dominant disorder. It includes cerebrovascular and cardiac anomalies, facial phenotype, hearing abnormality and developmental delay (2). Case: 41 yo, Female with history of HT since 2002 (high TSH, thyroid peroxidase antibody more than 1000 u/ml, low FT4 and FT3) on levothyroxine 150mcg/day. Recently moved to the USA from EL Salvador. Presented for initial evaluation. Denied smoking, alcohol, allergy. Maternal aunt with thyroid disease. Had menstrual irregularities, no previous attempt to conceive. Review of system: 5 months of pain, swelling and morning stiffness for 1 hour in hand joints, hearing difficulty for 2 years, painless brown skin spots for years, childhood learning difficulty and constipation. Physical examination body weight 139Ib, height 162cm, Stable vitals, diffuse lentigines. Head: board forehead, hypertelorism, high arched eye brows, micrognathia, low set ears. Heart: normal heart sounds, no murmur. No thyromegaly, nystagmus or vertigo. Hand: swelling of metacarpophalangeal and proximal interphalangeal joints. Laboratory work up TSH 8 normal 0.27 to 4.2 uIU/ml, FT4 0.8 normal 0.9-1.8 ng/dl, A1C 5.7, positive rheumatoid factor 199IU/ml, anti-CCP antibody > 250U, ANA 1/320, ESR 61ml/hr, negative anti-tissue transglutaminase antibody, normal liver and kidney function tests and complete blood count. Hand X-ray: decrease joint space and bone erosion. Thyroid US: normal size, vascularity, no nodule. Normal Echocardiogram, EKG and chest X ray. Internal auditory canal MRI: no masses or abnormal enhancement. DEXA Scan: osteopenia of femur and lumbar spine. She was diagnosed with seropositive RA, B/L sensorineural hearing loss (SNHL) more on right side. Genetic test revealed heterozygous pathogenic variant of PTPN11 gene consistent with NSML and negative for Neurofibromatosis type 1. Kept on prednisone and methotrexate, levothyroxine was increased 162mcg/day. Conclusion: Autoimmune disorders have a common pathogenesis including humoral and cell mediated immunity, autoimmune oxidative stress, UV radiation exposure, genetic linkage and biochemical changes. Diagnosis of one autoimmune disorder increases the possibility of other autoimmune disorders (1). NSML has a variable presentation. PTPN11-NSML is usually associated with SNHL and cardiac anomalies as pulmonary stenosis. It is infrequent to diagnose NSML with HT and structurally normal heart like our case(2). References: 1-Rose NR. predictors of autoimmune disease: autoantibodies and beyond. autoimmunity 2008;41:419. 2- Roberts AE, Allanson JE, Tartaglia M, Gelb BD. Noonan syndrome. Lancet 2013;381:333-42. Presentation: Saturday, June 17, 2023