Background: Ring chromosome 18 [r (18)] syndrome belongs to a rare group of chromosomal abnormalities (only about 70 cases reported). The association of r(18) and growth hormone deficiency (GHD) is extremely rare (3 descriptions with different responds to GH treatment). Patients with r(18) syndrome are characterized by short stature, obesity, microcephaly, mental retardation, hypertelorism, epicanthic folds, micrognatia and small hands with short tapering fingers. Also atypical manifestations have been observed, with facial anomalies only.
Case report: A 12 years old girl was referred to our clinic because of short stature. She was born at 36 weeks of gestation, her birth weight was 2200 g, length 51 cm, head circumference 32 cm. There was no family history of genetic or congenital disorders. The clinical examination revealed a girl with proportional short stature. Her height was 136 cm (−2,7 SDS), weight 40.6 kg, BMI 22.5 (1,1SDS), Tanner stage: 2 breast, 1 pubic hair development, discreet epicanthic folds, strabismus, lower-set ears and slightly smaller jaw. Her mental development was in lower normal range. Bone age was 10 years. GH stimulation tests showed a GHD (GH peak response to clonidine: 2.69 ng/ml, to insulin: 3.61 ng/ml). Baseline LH, FSH, TSH, prolactin and ACTH concentrations were in normal ranges for age. Magnetic resonance imaging of hypothalamic-pituitary region revealed a small hypophysis (2 mm). Chromosome analysis showed: 46, XX.ish r (18)(wcp18×1). No ultrasound abnormalities in abdomen and thyroid were shown. Echocardiogram showed minimal mitral regurgitation- clinically not relevant. GH replacement therapy was indicated with the dose of 0.33 mg/kg per day. After the first year of treatment she reached a height 146.8 cm (−1,8 SDS) with the height increase Δ 0,9 SDS. After the second year her height was 152.8 cm (−1,46 SDS), after the third:156.5 cm (−1,1SDS). Menarche occurred at the age 13 years 6 months.
Conclusion: Our patients growth response to GH treatment was similar to that observed in children with isolated GHD without r(18) syndrome. In children with r(18) exclusion of GHD should be taken under consideration.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology