Severe short stature due to 3-M syndrome with a novel OBSL1 gene mutation

3-M syndrome is an underdiagnosed autosomal recessive disorder characterized by severe pre- and postnatal growth retardation with minimal dysmorphic features and distinguishing radiological findings. We report a patient who was first admitted at 7.5 years of age. He was born to consanguineous parents with a birth weight of 2250 g. Physical examination revealed a severe short stature (height, 95 cm; SD score -5.64) and minimal dysmorphic features. Biochemistry, endocrine work-up, and karyotype were normal. Reevaluation at 16.5 years of age revealed a height of 128.5 cm (SD score -5.27), prominent forehead, anteverted nasal openings, fleshy nasal tip, full lips, malar hypoplasia, hyperlordosis, prominent heels, testicular volumes 8-10 mL, and pubic hair consistent with Tanner stage II. Growth hormone trial for a year resulted in inadequate height gain (3 cm). The diagnosis of 3-M syndrome was made upon typical findings (thin long bones with diaphyseal narrowing and tall lumbar vertebrae) in a recent skeletal survey. Genetic analysis disclosed a homozygote frame shift mutation in exon 2: c.457_458delinsT resulting in p.Gly153fs.