key: cord-0890962-xfntmay6
authors: McCann, Liza J.; McPartland, Jo; Barge, Dawn; Strain, Lisa; Bourn, David; Calonje, Eduardo; Verbov, Julian; Riordan, Andrew; Kokai, George; Bacon, Chris M.; Wright, Michael; Abinun, Mario
title: Phenotypic Variations of Cartilage Hair Hypoplasia: Granulomatous Skin Inflammation and Severe T Cell Immunodeficiency as Initial Clinical Presentation in Otherwise Well Child with Short Stature
date: 2013-11-12
journal: J Clin Immunol
DOI: 10.1007/s10875-013-9962-6
sha: c6a68f7cacaca07aeab83a794b1cc91cab1093ea
doc_id: 890962
cord_uid: xfntmay6

We report a child with short stature since birth who was otherwise well, presenting at 2.8 years with progressive granulomatous skin lesions when diagnosed with severe T cell immunodeficiency. When previously investigated for short stature, and at the time of current investigations, she had no radiological skeletal features characteristics for cartilage hair hypoplasia, but we found a disease causing RMRP (RNase mitochondrial RNA processing endoribonuclease) gene mutation. Whilst search for HLA matched unrelated donor for haematopoietic stem cell transplantation (HSCT) was underway, she developed rapidly progressive EBV-related lymphoproliferative disorder requiring laparotomy and small bowel resection, and was treated with anti-B cell monoclonal antibody and eventually curative allogeneic HSCT. Screening for RMRP gene mutations should be part of immunological evaluation of patients with ‘severe and/or combined’ T cell immunodeficiency of unknown origin, especially when associated with short stature and regardless of presence or absence of radiological skeletal features.

Cartilage-hair hypoplasia (CHH) (MIM #250250) is a rare autosomal recessive syndrome characterized by clinical features of metaphyseal dysplasia (short-limbed dwarfism) and light-coloured hypoplastic hair, bone marrow failure, defective spermatogenesis, an increased risk of Hirschsprung disease and malignancies, and variable degree of immunodeficiency [1] . CHH is caused by mutations of the untranslated RMRP gene, which encodes for the RNA component of the mitochondrial RNA processing (RMRP ) endoribonuclease complex. Disease-causing mutations in RMRP result in disruption of ribosomal processing and cell cycle progression in rapidly dividing cells such as lymphocytes and chondrocytes, thus explaining the pleiotropy of clinical manifestations [2] [3] [4] .

Despite individual variability, it has been recently shown that functional lymphocyte abnormalities are an integral component of CHH, with defects in thymic generation of T lymphocytes and in peripheral T-cell proliferation, cell cycle control, and activation-induced cell death [5] . In patients with clinical and laboratory features of (severe) T cell and/or combined immunodeficiency (CID) such as failure to thrive, recurrent severe infections (bacterial, fungal, viral), lymphopaenia with absent/low 'naïve' T cells and/or T cell function [5, 6] , allogeneic haematopoietic stem cell transplantation (HSCT) is the only curative treatment, although the skeletal abnormalities and the growth failure remains unaffected [7] .

Here we report progressive granulomatous inflammation as a leading clinical presentation of CHH due to RMRP gene mutation in an otherwise well child with short stature since birth, but no radiological features of skeletal dysplasia, associated with severe T cell immunodeficiency resulting in EBVrelated lymphoproliferative disease (LPD), eventually cured by allogeneic HSCT.

A 2 year 8 month female, the first child of unrelated Caucasian parents, presented with a 12 months history of initially small painless erythematous lesion affecting the right arm, gradually progressing in size ( Fig. 1a-b) , and a smaller lesion on the right leg. Except for recent ear infection with fever (38.6°C), there was no history of infections, bowel symptoms, foreign travel or exposure to mycobacteria (tuberculosis). She was fully vaccinated (except BCG), and had been previously investigated for persistent short stature since birth (height <0.4th percentile with mid-parental height of 50th percentile; weight 2nd percentile) but no underlying reason was found. She was short but proportionate, with fine blond hair, and with normal nails, teeth, body lanugo hair and sweating.

Initial investigations revealed raised inflammatory markers (ESR 96 mm/h; CRP 131 mg/l), significant neutropaenia (ANC 0.01-0.11×10e9/L), non-haemolytic anaemia (Hb 8.6 g/l, negative direct Coombs test, normal serum bilirubin), variable lymphopaenia (3.3-1.95×10e9/L), elevated serum immunoglobulin (Ig) M (4.62 g/l; range 0.5-2.0), and negative antinuclear, double stranded-DNA, ENA and antineutrophil antibodies. Bacterial, mycobacterial and fungal cultures (blood, skin) were negative, and viral serology nondiagnostic (positive EBV VCA IgM and IgG, CMV IgG, and negative VZV IgG and Parvovirus B19 IgM and IgG). Chest and bone (skeletal survey) radiography and abdominal ultrasound were normal. Bone marrow aspiration and biopsy (trephine) showed somewhat reduced erythroid series, and a reactive picture with significant left shift and good myeloid activity with increased numbers of eosinophils, although with a lack of maturation. The initial skin biopsy ( Fig. 1c -e) demonstrated CD3+ lymphocyte infiltrate and a T cell clone by T cell receptor (TCR) gene rearrangement analysis; EBV in-situ hybridization was negative as were mycobacterial PCR and fungal stains.

Further immunological investigations showed normal neutrophil oxidative burst and protective antibody titres to haemophilus influenzae type b (1.0 mg/l; range 1.0-20), tetanus (0.66 IU/ml; range 0.1-10) and pneumococcus (>0.35 mcg/l for 11/13 tested strains). However, she was found to have severe T cell immunodeficiency (Table I, Fig. 2 ) and viral infections (by PCR, EBV 5.5×10e4 and HHV6 2×10e3 (copies/ml) in blood, sapovirus in stool, adenovirus in nasal swab, and few EBVpositive cells were detected in the second skin biopsy).

Based on the features of short stature since birth, severe T cell immunodeficiency and unusual granulomatous skin inflammation, in spite of normal bone radiography (Fig. 3) , we searched for disease-causing mutations in the RMRP gene. Compound heterozyosity for a 13 bp duplication in the promoter (g.−26_−14 dup TACTACTCTGTGA) inherited from the mother (new mutation) and a nucleotide substitution (g.4C>T) close to the transcription initiation site inherited from the father (previously reported) confirmed the diagnosis (2,3). The severe T cell immunodeficiency and persistent EBV viraemia were indications for HSCT. However, before an unrelated (URD) donor was identified she developed abdominal pain and distension, fever and raised CRP (150 mg/l). Exploratory laparotomy revealed an ileal tumorous mass (Fig. 1f) which was resected and confirmed to be EBVrelated diffuse large B-cell lymphoma (Fig. 1g-i) . She was treated with anti-B cell monoclonal antibody (rituximab), and in June 2012 received 11.1×10e6/kg CD34+ peripheral blood stem cells from a 10/10 HLA matched URD after conditioning with alemtuzumab, treosulfan and fludarabine. Engraftment was uneventful (platelets day + 11; neutrophils day + 15) resulting in 100 % donor chimaerism. host disease (GvHD) at 3 weeks, treated with corticosteroids and TNF-alpha blocking agent (infliximab), autoimmune cytopenias (Coombs positive haemolytic anaemia, thrombocytopaenia and neutropaenia) at 3 months, treated with corticosteroids, immunomodulatory high-dose intravenous Ig (IVIg) and rituximab, and viral reactivation and/or new infections (parainfluenza III, adenovirus, HHV6, rhinovirus, coronavirus, norovirus) of which only persistent HHV6 viraemia (10e4-10e5/ml) and biopsy-proven enterocolitis needed treatment (ganciclovir, valganciclovir, foscarnet). One year post-HSCT she is well with markedly receded granulomatous skin lesions, only on IVIg substitution and azithromycin prophylaxis. Chimaerism remains 100 % donor in myeloid, T and B cell lineages, she has normal numbers of naïve 'early thymic emigrant' T cells, in vitro proliferation to PHA, and emerging B cells and serum IgM post-rituximab.

The clinical features of CHH are more heterogeneous than usually thought [1, 2] , with marked variability of immunological phenotype [5, 6, 8] and radiographic features [9] . Importantly for the diagnostic process, as illustrated by our case, the Fig. 2) , with unusually high proportion of T lymphocytes expressing TCR-gamma/delta (usually <10 %) (no clonality studies of this cell population were performed). Some of these features may be due to the chronic viral (EBV) infection, although there is a complete lack of the 'effector' CD8+ T cell population (CD45RA+/CD27-) which would otherwise be expected to be expanded CD cluster of differentiation; NK natural killer; HLA human leukocyte antigen; MHC major histocompatibility complex; PHA phytohaemmaglutinin; PMA pokeweed mitogen; cpm counts per minute; IL interleukin characteristic skeletal abnormalities should not always be expected to be present, particularly in early childhood [9, 10] . Bone marrow failure is common, as in our patient, with hypoplastic anaemia reported in~80 %, lymphopaenia iñ 60 %, and neutropaenia in~25 % of patients [11] . Skin granulomatous inflammation can be caused by infections (mycobacteria in particular), inflammatory conditions (sarcoidosis, inflammatory bowel disease, Blau syndrome etc.), but may also be a feature of primary immunodeficiency disorders associated with marked immune dysregulation such as common variable immunodeficiency, chronic granulomatous disease, combined/T cell immunodeficiency, etc.

[reviewed in 12] . Omenn syndrome has been reported in patients with RMRP mutations [13] , and a variety of patients classified as 'short-limbed skeletal dysplasia with combined immunodeficiency' (MIM 200900) presented with skin features such as ectodermal dysplasia [14] and granulomatous lesions [15] . Moshous et al. described inflammatory granulomas as a new clinical feature in 4 out of a series of 21 patients with CHH [16] , and a further case of extensive granulomatous lesions was reported recently in a foetus [17] . Similar to ours, these 5 patients with proven RMRP mutation had severe CD4 T cell lymphopaenia [16, 17] . Even in otherwise clinically 'mild' phenotype [10] , severe T cell lymphopaenia should not be undermined. Our patient clearly demonstrated one of the hallmarks of severely impaired T cell immunity due to RMRP mutation, the poor handling of the herpes family of viruses, with development of life-threatening EBV-related LPD [1, 5] . The only curative therapy is allogeneic HSCT [7] , highlighted by the 'natural history' observed during the long-term follow up of a child diagnosed with CHH at the age 8 years, who at the age 32 years presented with relapsing EBV-related anaplastic large cell lymphoma and granulomatous lymphomatoid papulosis, both conditions being part of the spectrum of primary cutaneous CD30+ T cell LPD, and who died 14 years after the primary diagnosis of lymphoma in spite of several courses of chemotherapy [18] . A recent insight in the role of dysregulated long non-coding RNAs in cancer initiation and progression, in the case of RMRP specifically related to leukemia and lymphoma [19] further expands our understanding of the well recognised increased incidence of cancer in patients with CHH, particularly non-Hodgkin lymphoma and basal cell carcinoma [20] . All this evidence strongly suggests that patients with severely impaired T cell immunity due to RMRP mutation should be classified in the group of "severe and/or combined primary immunodeficiencies" [21] [22] [23] [24] .

We present a patient with granulomatous lesions and severe T cell immunodeficiency due to RMRP gene mutation, who developed rapidly progressive and life-threatening EBVrelated LPD.

Screening for RMRP gene mutations should be part of immunological evaluation of patients with 'severe and/or combined' immunodeficiency of unknown origin, especially if associated with short stature and/or granulomatous inflammatory lesions, irrespective of presence or absence of radiographic features characteristic for cartilage hair hypoplasia.

Allogeneic haematopoietic stem cell transplantation is the only curative treatment for immunodeficiency, while growth failure remains unaffected.

The authors declare that they have no conflict of interest.

Consent Informed consent has been obtained from the patient's parents for the case report and medical photographs used in this manuscript. All studies have been performed in accordance with the 1964 Declaration of Helsinki and its later amendments.

Contributor's Statement Liza J McCann, Jo McPartland, George Kokai, Chris Bacon, Julian Verbov and Andrew Riordan were involved in direct patient care and/or diagnostic process, provided patient data, and reviewed and approved the manuscript.

Dawn Barge performed and interpreted the immunological investigations results for the manuscript, and reviewed and approved the manuscript. Eduardo Calonje interpreted the histopathology findings of the skin biopsy, and reviewed and approved the manuscript.

Lisa Strain and David Bourn performed and interpreted the genetic mutation analysis, and reviewed and approved the manuscript.

Michael Wright was involved in direct patient care and diagnostic process, interpreted the skeletal radiography and genetic mutation analysis, and reviewed and approved the manuscript.

Mario Abinun was involved in direct patient care and diagnostic process, and wrote the manuscript.

Immunodeficiencies with associated manifestations of skin, hair, teeth, and skeleton

Type and level of RMRP functional impairment predicts phenotype in the cartilage hair hypoplasia-anauxetic dysplasia spectrum

The molecular basis of the cartilage-hair hypoplasia-anauxetic dysplasia spectrum

Small RNAs derived from lncRNA RNase MRP have gene-silencing activity relevant to human cartilage hair hypoplasia

Reduced thymic output, cell cycle abnormalities, and increased apoptosis of T lymphocytes in patients with cartilage-hair hypoplasia

Variability of clinical and laboratory features among patients with ribonuclease mitochondrial RNA processing endoribonuclease gene mutations

Clinical and immunologic outcome of patients with cartilage hair hypoplasia after hematopoietic stem cell transplantation

Cartilage-hair hypoplasia: molecular basis and heterogeneity of the immunological phenotype

Marked variability in the radiographic features of cartilage-hair hypoplasia: case report and review of the literature

Mild clinical phenotype and subtle radiographic findings in an infant with cartilage-hair hypoplasia

Anaemia and macrocytosis-unrecognized features in cartilage-hair hypoplasia

The role of the innate immune system in granulomatous disorders

Mutations in the RNA component of RNase mitochondrial RNA processing might cause Omenn syndrome

Hereditary lymphopenic agammaglobulinemia associated with a distinctive form of short-limbed dwarfism and ectodermal dysplasia

Granulomatous reaction in an infant with combined immunodeficiency and short-limbed dwarfism

Granulomatous inflammation in cartilage-hair hypoplasia: risks and benefits of anti-TNF-a mAbs

Foetal presentation of cartilage hair hypoplasia with extensive granulomatous inflammation

Combating cancer predisposition in association with idiopathic immune deficiency: a recurrent nodal and cutaneous T-cell lymphoproliferative disease in a patient with cartilage-hair hypoplasia

Long non-coding RNAs: a new frontier in the study of human diseases

Increased incidence of cancer in patients with cartilage-hair hypoplasia

Unravelling the association of partial T cell immunodeficiency and immune regulation

Primary immunodeficiency diseases: an update on the classification from the International Union of Immunological Societies Expert Committee for Primary Immunodeficiency

Defining combined immunodeficiecny

Classification of primary immunodeficiency: need for a revised approach

Acknowledgments We are grateful to Drs Ali Al-Sharqi, Poonam Dharmaraj, Helen Campbell and Eileen Baildam, Alder Hey Children's NHS Foundation Trust, Liverpool and the staff at the Children's Bone Marrow Transplantation Unit, Great North Children's Hospital, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, for their involvement in management of the patient.Declaration of Funding None.