Dyggve-Melchior-Clausen Syndrome

The clinical presentation of Dyggve-Melchior-Clausen syndrome (DMC), initially described approximately 50 years ago [1], is distinguished by a combination of several features that develop in early childhood [1] [2] [3] [4] [5] [6]:

• Skeletal changes - The most prominent feature of DMC syndrome is a very short stature, with standard deviation scores (SDS) reaching as low as -12.6 SD in some reports [1]. The upper part of the body seems to be more severely affected and a pigeon-shaped (or barrel) chest is one of the hallmarks of Dyggve-Melchior-Clausen syndrome [1]. Rhizomelic limb shortening is an accompanying feature [1] [3]. Lumbar lordosis, brachydactyly, and broad interphalangeal joints are seen in up to 100% of patients, whereas scoliosis, kyphosis, protrusion of the sternal bone, genu valgum or varum, and limited joint extension are other notable manifestations that develop in up to 50% of individuals [1] [6].
• Mental retardation - The second crucial feature of DMC syndrome is mental retardation, varying from moderate to severe [1].
• Craniofacial changes - Virtually all patients who suffer from DMC syndrome develop microcephaly and a disproportionate development of the skull and facial bones compared to the brain size [1] [5]. In addition, characteristic facial changes include a narrow forehead, thick lips, macrognathia, prominent ears, and macrostomia [1].

Other notable findings are a protruded abdomen and generalized hirsutism [1].

Because Dyggve-Melchior-Clausen syndrome is very rare, the diagnosis may be difficult to attain without a thorough diagnostic workup. Since affected children develop the typical clinical presentation in the first several years of life, the physician should first obtain a detailed patient history from the parents. The history should cover the onset of symptoms and their progression, as well as severity. The fact that many identified patients either come from consanguineous marriages or have first-degree relatives who already suffer from Dyggve-Melchior-Clausen syndrome makes a complete family history crucial for identifying a genetic background of the disease. As soon as clinical suspicion is raised, imaging studies should be employed. Plain radiography of the axial skeleton, the pelvis, and the limbs is the key step for determining the exact type of deformity [1] [3]. One of the most specific findings seen in this syndrome is the lace-like character of the iliac crests. Small iliac wings, bilateral hip dislocation, a widened pubic symphysis, acetabular hypoplasia, a wide sacroiliac joint and deformed femoral heads are other prominent findings in the hips in these patients [1] [3]. A barrel-shaped chest with broad ribs, platyspondyly, and a double-hump shape of the bone end-plates provide sufficient evidence to make a solid diagnosis of Dyggve-Melchior-Clausen syndrome [1] [3]. Genetic studies can be used as a definitive method, which confirm mutations of the dymeclin gene located on chromosome 18 [1] [2] [4] [5] [6].

1. Aglan MS, Temtamy SA, Fateen E, Ashour AM, Eldeeb K, Hosny GA. Dyggve–Melchior–Clausen syndrome: clinical, genetic, and radiological study of 15 Egyptian patients from nine unrelated families. J Child Orthop. 2009;3(6):451-458.
2. Dyggve HV, Melchior JC, Clausen J. Morquio-Ullrich’s disease: an inborn error of metabolism? Arch Dis Child. 1962;37:525–534.
3. Beighton P. Dyggve–Melchior–Clausen syndrome. J Med Genet. 1990;27:512–515.
4. Thauvin-Robinet C, El Ghouzzi V, Chemaitilly W, et al. Homozygosity mapping of a Dyggve–Melchior–Clausen syndrome gene to chromosome 18q21.1. J Med Genet. 2002;39:714–717.
5. Ehtesham N, Cantor RM, King LM, et al. Evidence that Smith–McCort dysplasia and Dyggve–Melchior–Clausen dysplasia are allelic disorders that result from mutations in a gene on chromosome 18q12. Am J Hum Genet. 2002;71:947–951.
6. Gupta V, Kohli A, Dewan. Dyggve melchior clausen syndrome. Indian Pediatr. 2010;47(11):973-975.