The condition named Kabuki make-up syndrome (KS) is a rare multiple anomaly syndrome. The name was attributed because of the facial resemblance to the make-up used in traditional Japanese Kabuki theatre. It was first described in 1981 by Niikawa[
1] and Kuroki[
2,
3]. The estimated prevalence of KS in Japan was 1/32,000 people with almost equal sex distribution. Although it was initially considered as a disease affecting exclusively the Japanese population, several reports support a widespread ethnic distribution of KS[
4]. The main clinical characteristics are distinctive facial features: elongated palpebral fissures with eversion of the lateral third of the lower eyelid; arched and broad eyebrows; short columella with depressed nasal tip; large, prominent, or cupped ears. Other findings may include: minor skeletal anomalies, persistence of fetal fingertip pads, from mild to moderate intellectual disability, postnatal growth deficiency, congenital heart defects, genitourinary anomalies, cleft lip and/or palate, gastrointestinal anomalies. Functional differences can include:seizures, endocrinologic abnormalities (premature thelarche in females, feeding problems, hearing loss), hypogammaglobulinemia, increased susceptibility to infections and autoimmune disorders as idiopathic thrombocytopenic purpura (ITP), haemolytic anemia, thyroiditis and vitiligo[
5,
6]. The prevalence of major findings is summarised in the table (Table
1)[
7‐
12]. Genetic basis of KS has been recently elucidated. Mutations in the mixed lineage leukaemia 2 gene,
KMT2D (formerly
MLL2) mapping on chromosome 12q13.12, are described in 55-80% of KS patients[
13]. KMT2D is a histone H3 lysine 4 (H3K4)-specific methyl transferase that belongs to the SET1 family of human SET-domain protein methyltransferase superfamily. KMT2D acts as a part of multiprotein complex named ASCOM. It interacts with oestrogen receptor-α and it is important for epigenetic transcriptional activation and for embryonic development[
14]. KMT2D has emerged as one of the most frequently mutated genes in a variety of cancers, including lymphoma, medulloblastoma and gastric cancer, thus supporting a role as a tumor suppressor in various tissues[
15]. In patients without
KMT2D mutation,
KDM6A gene mutations have been reported. Lederer and Miyake described, respectively, deletion and point mutations as cause of KS[
16,
17].
KDM6A located at Xp11.3 encodes the lysine demethylase 6A demethylating di-and trimethyl-lysine 27 on histone H3. Like KMT2D, KDM6A plays an important role in embryogenesis and development[
18]. In a recent multicenter study short stature and postnatal growth retardation were observed in all individuals with
KDM6A mutations, but in only half of the group with
KMT2D mutations[
19]. As KS is a multisystemic disorder, people with KS may require various diagnostic and screening tests, assessments, referrals and multidisciplinary interventions at different stages of their lives[
9‐
12]. For these reasons in 2011, the panel of DYSCERNE team (a network of centres of expertise for dysmorphology), funded by the European Commission Public Health Executive Agency, wrote the “Kabuki Syndrome Clinical Management Guidelines”[
20]. These guidelines have been developed using a robust methodology based on the one used by the Scottish Intercollegiate Guidelines Network (SIGN). The method has been adapted to suit rare conditions where the evidence base is limited, and where expert consensus plays a greater role. Of note in the natural history of the KS, an abnormal immune regulation may occur. Some authors reported their experiences in the treatment of KS patients with immunodeficiencies[
21] or autoimmune disorders[
22]. In this paper, we contribute to the list describing two Italian KS children with autoimmune haematological disorders and their clinical management.
Table 1
The prevalence of major findings in more than 350 individuals with Kabuki syndrome (KS)
Typical facial features* | ~ 95 |
Intellectual disability | 92 |
Hypotonia | 25-89 |
Postnatal growth retardation | 35-81 |
Joint hypermobility | 50-75 |
Feeding difficulties | 70 |
Congenital heart defects | 40-50 |
Premature thelarche | 7-50 |
Hearing loss | 40 |
Seizures | 10-39 |
Ocular anomalies | 33 |
Cleft lip and/or palate | 33 |
Renal and urinary tract anomalies | 25 |
Immune dysfunction: | ~ 20 |
Hypogammaglobulinemia, | |
Idiopathic Thrombocytopenic Purpura (ITP), Autoimmune haemolytic anemia, | |
Thyroiditis | |
Vitiligo | |