Summary

3M syndrome combines pre- and post-natal proportionate growth retardation, characteristic facial dysmorphism (known as 'gloomy facies'') and radiological abnormalities. It is a very rare condition and less than 50 patients have been reported so far. '3M'' stands for the initials of the three authors who first described this syndrome. The characteristic facial features, present at birth, are: a relatively large head, dolichocephaly, frontal bossing, a triangular face, pointed chin, upturned nose, full lips, full eyebrows, long philtrum and hypoplastic midface. Radiological findings, which are observed later in childhood, are slender long bones and ribs, and foreshortened vertebral bodies. Other characteristics are: a short neck, prominent trapezius, square shoulders, short thorax, pectus excavatum or carinatum, hyperlordosis, increased mobility of joints, short fifth fingers and male gonadal dysfunction with normal puberty but sub- or infertility. Intelligence is normal. The range and severity of symptoms and physical features may vary from case to case. 3M syndrome is transmitted as an autosomal recessive trait. It is caused by mutations in the cullin-7 gene (CUL7, 6p21.1). Prenatal diagnosis is possible by ultrasonography. Growth hormone treatment can be proposed to increase final height.