|LETTER TO EDITOR
|Year : 2022 | Volume
| Issue : 3 | Page : 203-204
Hereditary sensory and autonomic neuropathy type IC with SPTLC2 mutation associated with immune thrombocytopenia
Mansoor C Abdulla
Department of General Medicine, Nizar Hospital, Valancheri, Kerala, India
|Date of Submission||15-Feb-2022|
|Date of Decision||17-Feb-2022|
|Date of Acceptance||19-Feb-2022|
|Date of Web Publication||13-Jul-2022|
Prof. Mansoor C Abdulla
Department of General Medicine, M.E.S. Medical College, Perinthalmanna - 679 338, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Abdulla MC. Hereditary sensory and autonomic neuropathy type IC with SPTLC2 mutation associated with immune thrombocytopenia. Indian J Med Spec 2022;13:203-4
|How to cite this URL:|
Abdulla MC. Hereditary sensory and autonomic neuropathy type IC with SPTLC2 mutation associated with immune thrombocytopenia. Indian J Med Spec [serial online] 2022 [cited 2022 Aug 15];13:203-4. Available from: http://www.ijms.in/text.asp?2022/13/3/203/350773
Hereditary sensory and autonomic neuropathy Type IC (HSAN Type 1C) (OMIM#613640) is caused by heterozygous mutations in the SPTLC2 gene (OMIM × 605713). Thrombocytopenia in a patient with peripheral neuropathy can be seen with autoimmune diseases (systemic lupus erythematosus or rheumatoid arthritis), chronic infections (human immunodeficiency virus [HIV], Lyme disease, hepatitis B, and hepatitis C), nutritional diseases (B12 deficiency), or inflammatory diseases (sarcoidosis).
A 27-year-old male presented with a history of progressive loss of sensations and weakness of both upper and lower limbs distally for 2 years. He denied history of high-risk behavior or any chronic illness in the past and had no addictions or sick contacts. He was born as the first child of a nonconsanguineous union by vaginal delivery at term without complications. His parents and siblings were normal. He was obese, had purpura over the lower limbs, high blood pressure (150/100 mmHg), and tachycardia. Nervous system examination showed mild weakness of both upper and lower limbs distally with absent lower limb deep tendon reflexes and loss of pain and temperature sensations in all four limbs in a glove and stocking distribution. Joint/position sense and vibration were reduced in the lower limbs distally.
Hemoglobin was 14.8 g/dl, total leukocyte count 6100 mm3 with normal differential, platelet count was 15,000/microliter, and erythrocyte sedimentation rate 27 mm in 1 h. The peripheral smear showed severe thrombocytopenia. Blood chemistries, prothrombin time, and activated partial thromboplastin time were within normal limits. Bone marrow examination showed increased megakaryocytes with normal maturation. The serum platelet-associated immunoglobulin G (IgG) levels were elevated.
Nerve conduction studies showed axonal neuropathy with secondary demyelination. Workup for peripheral neuropathy including HIV, hepatitis B and hepatitis C serology, antinuclear antibodies, antineutrophil cytoplasmic antibodies, urine porphobilinogen, serum-free light-chain assay, serum immunofixation electrophoresis, serum Vitamin B12 and folic acid, serum IgG4, paraneoplastic antibodies, and fluorodeoxyglucose-positron emission tomography, serum angiotensin-converting enzyme, and toxicology screening for heavy metals were negative. Nerve biopsy showed severe axonal degeneration without significant inflammatory infiltrates. Exome sequencing revealed a heterozygous missense variant in exon 8 of the SPTLC2 gene (chr14: g. 77555328G >A) resulting in the amino acid substitution of valine for alanine at codon 383 (p. Ala383Val). Genetic test was not done for the other members of the family. On the basis of clinical features and molecular analysis, the patient was diagnosed to have HSAN Type 1C. The family has been counseled that this is a genetic condition with autosomal dominant inheritance. He was treated with steroids for immune thrombocytopenia (ITP) which was tapered later.
A combination of thrombocytopenia with peripheral neuropathy can be seen with autoimmune diseases (systemic lupus erythematosus or rheumatoid arthritis), chronic infections (HIV, Lyme disease, hepatitis B, and hepatitis C), nutritional diseases (B12 deficiency), or inflammatory diseases (sarcoidosis). This patient was evaluated extensively for the cause of peripheral neuropathy because of the associated thrombocytopenia considering the possibility of an underlying systemic disease. Exome sequencing was done for this patient since all other tests for peripheral neuropathy were negative. Intraneural bleeding, immune-mediated neuropathy, and vasculitis are the possible mechanism of neuropathies in ITP.,, None of these causes were detected in this patient.
HSAN Type 1C is an autosomal dominant disorder characterized by sensory loss, distal limb weakness, and variable autonomic dysfunction. Most patients have adult onset of slowly progressive distal sensory impairment as well as distal muscle atrophy. Electrophysiologic studies show a predominantly axonal neuropathy with some demyelinating features. Some patients may have evidence of central nervous system involvement, including macular telangiectasia Type 2 and/or pyramidal signs. Asn177Asp mutation in SPTLC2 with predominant motor deficits, but no or minimal sensory or autonomic complaints were described previously. HSAN Type 1C does not have any association with ITP.
To conclude, we report a patient with HSAN Type 1C who was also found to have ITP. This is more likely a chance association. Coexistence of ITP and peripheral neuropathy will make us all think of systemic diseases such as autoimmune diseases, chronic infections, and inflammatory diseases. Genetic studies to identify a hereditary neuropathy may be considered after excluding other causes.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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