The patient was referred to our third-level Paediatric Endocrinology Unit when she was 9 years old for short stature and suspected precocious puberty. She was of Russian origin and was adopted at the age of 2 years. Limited data were available about her family and perinatal history. The biological mother was affected by insulin-dependent diabetes mellitus and arterial hypertension. Nothing was known about the biological father. No data were available about gestational age, neonatal weight and length as well as general conditions at birth. She was born with agenesis of the right tibia and fibula, and underwent mid-thigh amputation when she was 5 years old. She also presented a supernumerary digit of the left foot, which was excised when she was 8 years old.
At the age of 9 years, she was referred to our Paediatric Endocrinology Unit for short stature and with potential precocious puberty. Her height was <3rd percentile on CDC growth charts for sex and age (parental target was not known), her weight was in the 25th percentile (http://www.cdc.gov/growthcharts) with a body mass index in the overweight range according to International Obesity Task Force cut-offs [5]. The pubertal stage was a B3 PH2 according to Tanner criteria. She had dorsal scoliosis, a short neck, upturned nose and hypotelorism (Fig. 1). Her systolic and diastolic blood pressure values were in the 90th percentile for sex and height. Biochemical evaluations excluded celiac disease and revealed a normal blood cell count, normal thyroid, kidney, liver and adrenal function. The levels of LH/FSH were > 1 (LH 8.6 mIU/ml, FSH 7.5 mIU/ml) with pubertal oestrogens level, normal fasting insulin and glucose levels with normal glycosylated haemoglobin. Growth hormone (GH) secretion, which was evaluated by Arginine and L-Dopa provocative tests (2.5 ng/ml and 6.8 ng/ml, respectively), revealed a GH deficiency. Cerebral magnetic resonance (MR) showed that her pituitary gland had anormal size, morphology and contrastographic characteristics. Echocardiography and abdominal ultrasonography were performed, and there were no pathological findings. In particular, pelvic ultrasonography showed a uterus with an apparent normal size and morphology as well as a thin endometrium and ovaries with an initial follicular pattern, but the reliability of the exam was limited by bowel gases.
Treatments with human recombinant GH and triptorelin were started to achieve the best growth gain. Triptorelin was able to block the puberty progression. At 14 years, triptorelin was withdrawn, and, at 15 years, menarche appeared. Her final height was 137.5 cm, which corresponds to <3rd percentile.
When she was 17 years old, she complained severe abdominal pain during a menses. A pelvic ultrasonography was performed revealing a picture of hematocolpos. The abdomen MR showed uterus didelphys with double vagina. Due to the presence of these uro-genital anomalies, arterial hypertension at a young age and the family history for insulin-dependent diabetes, molecular analyses of the HNF-1β gene was performed. No alteration was found in this gene.
Because of the complexity of the case with multi-system involvement, array comparative genomic hybridization (aCGH) analysis was performed using the standard Agilent Human Genome G3 SurePrint 8x60K Microarray (Agilent Technologies, California, USA). Two distinct duplications flanking the SHOX gene on Xp22.1 (Fig. 2) and an additional duplication of 1.6–2.5 Mb on 15q25.2 (Fig. 3) were detected. To better characterize the Xp22.1 imbalances, confirmed by MLPA, a custom CGH array was used with a high probe density (371 bp average probe spacing) in the PAR1 region (Fig. 2). This analysis revealed the presence of a triple dose of two distinct segments of 302 Kb (chrX:192,136–494,191 × 3, NCBI build 37, hg 19) and 767 Kb (chrX:686,753–1453,835 × 3) that included the upstream and downstream enhancer regions respectively, whereas the SHOX coding gene was present in two normal copies (Fig. 2).
The presence of the 15q25.2 duplication was confirmed through MLPA (Multiplex Ligation Probe Amplification) with a probe specifically designed within the CPEB1 gene. The 15q25.2 duplicated region was examined using the Human resource websites (https://www.ncbi.nlm.nih.gov/projects/genome/guide/human/) at NCBI and the Archive EnsEMBL (https://www.ensembl.org/info/website/archives/index.html). This region contains 13 genes, some of them with a known function (Additional file 1: Table S1). Three of these, namely RPS17, CPEB1 and HOMER, have been previously associated to well defined disorders albeit none of these is apparently related to the clinical features observed in our patient.
Unfortunately, the biological parents were not available to establish the origin of the duplications.
We performed a search in DECIPHER database (https://decipher.sanger.ac.uk/) and identified 4 patients carrying similar micro-duplications (Fig. 3).