Abstract 69: A novel variant of MTHFR homozygous mutation causing hyperhomocystinemia in a case presenting as tall stature

Background: Tall stature is an important challenge in clinical practice. Case Report: We report case 2 brothers, Elder one 17-year-old boy presented with tall stature and mental retardation; his height was 178 cm (90 centile) with MPH of 164 (10 centile). Upper segment to lower segment rati of 0.85. He had high arch palate, arachnodactyly, with chest deformity, scoliosis, genu valgum. His intelligence quotient was 58. His Serum Homocystine level was 199.95 micromol/L (normal range 5.45 -16.2). His younger brother, who had the same mutation, had 165 cm (90 centile) height at the age of 13 years. The younger one serum homocystine levels was 166 micromol/L. Whole exome sequencing revealed a homozygous novel missense mutation in the MTHFR gene in exon 12 (c.1874A>C (p.Lys625Thr)). Methylenetetrahydrofolate reductase (MTHFR) deficiency is a rare inborn error of metabolism that cause hyperhomocysteinemia with homocystinuria, or mild hyperhomocysteinemia, which in turn leads to mental retardation, psychiatric disturbances, thromboembolic phenomena, and skeletal abnormalities such as osteoporosis, and tall stature. Conclusion: We report two brothers with novel variant of MTHFR homozygous mutation causing hyperhomocystinemia in a case presenting with tall stature.