Kabuki syndrome (KS) is a genetic syndrome characterised by typical facial features (palpebral fissures with inverted lower eyelids, arched eyebrows, depressed nasal tip), musculoskeletal abnormalities (brachydactyly, clinodactyly of the fifth digits and spine abnormalities), abnormal epidermal ridges, short stature, and intellectual deficit1.

Although the association between KS and autoimmune disease is well documented, probably due to mutations in the dysregulation of lymphocyte differentiation2,3, this is the first reported case of association with primary juvenile Sjögren’s syndrome (jSS).

We present the case of a 9-year-old Caucasian girl diagnosed with KS (15654C>G mutation in exon 48 of gene KMT2B) and father with systemic lupus erythematosus (SLE).

Her symptoms started with xerophthalmia (red eye, stinging sensation and ocular lacrimation) associated with xerostomia (drinking more than 3 l of water per day, including night waking) and occasional mouth ulcers. She reported intermittent polyarthralgia, without oedema or stiffness. No history of parotitis or Raynaud’s phenomenon.

On examination, she presented dysmorphic features typical of KS, joint hypermobility without arthritis, cutaneous xerosis, cracked tongue and impalpable salivary glands.

Laboratory tests reported normal haemogram, elevated amylase, ANA 1/1000 with speckled pattern, positive anti-SSa, normal complement and mild hypergammaglobulinaemia. Inflammatory markers, urinary sediment and the remaining immunological study were normal. Salivary gland ultrasound (SGUS) showed normal dimensions, heterogeneous parenchyma, and hypoechoic areas, compatible with jSS. Biopsy of the minor salivary glands was normal.

She was observed by the ophthalmology department who confirmed keratoconjunctivitis sicca, with positive Schirmer test and Ocular Staining Score ≥5.

Due to transient liver function elevation, she underwent a liver autoimmunity panel, which was negative. The elevated liver function in this syndrome could be due to autoimmune hepatitis or primary biliary cirrhosis, and was therefore excluded.

She started treatment with general measures for xerostomia and oral hygiene, ocular lubrication, and skin hydration. During follow-up she developed mild photosensitive malar erythema. Due to the risk of overlap with SLE and mild systemic manifestations (arthralgias and hypergammaglobulinaemia), treatment was started with hydroxychloroquine 4 mg/kg/day.

We now know that SS is an autoimmune disease characterised by T-lymphocyte infiltration at the level of the exocrine glands. This infiltration leads to destruction of the exocrine glands and the onset of symptoms related to dryness of the infiltrated mucous membranes. Up to one third of patients may present with more active and severe extraglandular manifestations that affect long-term prognosis2–4.

In children SS is rarely primary, as in our case, and therefore close monitoring is essential in this type of patient due to the risk of overlap with another connective tissue disease5.

There are currently no diagnostic criteria for SS in the paediatric age group; adult criteria depend too much on evidence of glandular dysfunction, which takes time to develop and is less evident during childhood. Biopsy at this age has a low sensitivity due to the small size of the glands, diagnostic difficulty and being able to biopsy an area that is normal5. Nevertheless, our patient meets the 2016 ACR/EULAR criteria6.

There are international groups that are working on diagnostic criteria for SS adapted to the paediatric age group. Since we know that recurrent mumps is the most typical form of presentation in this age group, including this entity in these criteria seems to increase diagnostic sensitivity for jSS. It is possible that the combination of salivary gland inflammation (clinical or subclinical parotitis, SGUS or histopathology changes) and positive autoantibody may be sufficient to diagnose SS in a child.

If there are suggestive symptoms, patients with KS should always be thoroughly assessed for autoimmune disorders. This is the first case described in the literature of both syndromes.