ESPE Abstracts

Introduction: Diploid/triploid mosaicism is an uncommon clinical syndrome presenting with developmental retardation and a distinctive phenotype: prenatal and postnatal asymmetric growth deficiency, distinctive facial dysmorphism, hands and feet malformations with a wide sandal gap, pigmentary dysplasia, hypotonia and hypotrophy of the musculature, and truncal obesity. However, metabolic syndrome was not reported in these patients. Diploid/triploid mosaicism may be diagnosed by cytogenetic analysis of skin fibroblasts but not from peripheral blood.

Aim: To report two female patients with diploid/triploid mosaicism who developed features of metabolic syndrome at an early age.

Case reports: Patient 1: During pregnancy IUGR was observed. She was born at GA 39 weeks: BW 1850 g (-3,57 SD), BL 43 cm (-3,68 SD). During early childhood, dysmorphic features and developmental delay were noted, and the patient developed truncal obesity. At 5 years of age hyperglycaemia was found during methylprednisolone therapy for bronchial obstruction and recovered spontaneously. At the age of 11 years, she developed type 2 diabetes mellitus (HbA1c 7,3%, BG 16 mmol/L, insulin 37,6 mU/L), dyslipidaemia, liver disorder, hyperuricaemia, and soon after significant albuminuria. Wide cytogenetic and genetic investigations were performed without any suggestive findings. Patient 2: Born from pregnancy complicated with IUGR, at GA 39 weeks, BW 1700 g (-3,7 SD), BL 43 cm (-3,5 SD). She had hypotonia, respiratory distress, distinctive dysmorphism, multiple malformations, hypoplastic/dysplastic left kidney, and impaired hearing that led to cytogenetic evaluation, which finally revealed diploid/triploid mosaicism from skin biopsy samples. She developed truncal obesity very early. At the age of 4.5 years, the patient suffered from generalised convulsions. Soon after, hyperglycaemia was observed following glucocorticoid therapy (glucose up to 28 mmol/L, HbA1c of 6,8%), dyslipidaemia, hyperuricaemia, and liver disorder were noted at that time, followed by albuminuria a year later, even though glycaemia normalised with diet. Soon after the diagnosis of patient 2, due to similar phenotypic features, punch biopsy of the skin was performed in patient 1 and diploid/triploid mosaicism was also found.

Conclusion: In patients with specific dysmorphism that present at an early age with features of metabolic syndrome, diploid/triploid mosaicism should be suspected, and a skin biopsy should be performed because it cannot be diagnosed from a blood sample. In children with known diploid/triploid mosaicism, early screening for metabolic disorders and preventive interventions should be considered.