Costello Syndrome

A syndrome characterized by postnatal growth deficiency, coarse facies, redundant skin on the neck, acanthosis nigricans, developmental delay, and papillomata.

(Figure)

Fasciocutaneoskeletal Syndrome; Mental Retardation Papillomata Syndrome.

Approximately 50 cases have been described in the literature.

Most likely autosomal dominant.

The abnormalities stem from abnormal development of ectodermal tissue, the mechanism of which is not understood. The responsible gene is located on 22q13.1. The etiology of Costello syndrome is unclear. Fibroblasts show increased proliferation, normal elastin gene expression, produce normal amounts of tropoelastin, and properly deposit an extracellular microfibrillar scaffold; however, the assembly of elastic fibers is defective secondary to rapid shedding of elastin binding proteins. This finding has been suggested to result from accumulation of chondroitin sulfate moieties, a phenomenon also found in Mucopolysaccharidosis.

Clinical recognition of the peculiar course of the disease, typical facies, and ectodermal involvement (loose and hyperpigmented skin).

Pregnancy is frequently complicated by polyhydramnios. Respiratory distress immediately after birth has been reported in a few patients. Characteristically, patients are born with increased birth weight and macrocephaly, which is followed by postnatal growth retardation and failure to thrive. Patients often require an enteral feeding tube because of oral motor apraxia and swallowing problems. This period is called the marasmic phase, which is followed by the pseudo-thesaurismotic phase that is characterized by a storage disease-like picture with macrocephaly, full cheeks, large mouth with thick lips, macroglossia, and gingival hyperplasia. The disease involves the head and neck (macrocephaly, coarse facies, strabismus, keratoconus, chorioretinal dystrophy, hypertelorism, epicanthal folds, downslanting palpebral fissures, low-set ears with fleshy earlobes and helices, depressed nasal bridge with bulbous nose and anteverted nostrils, full cheeks, micrognathia, retrognathia, large mouth with macroglossia, high arched palate, bifid uvula, abnormal teeth, short neck), the skeleton (short stature with adult height between 118 and 148 cm, barrel chest, pectus excavatum/ carinatum, scoliosis, broad hands and feet, limited extension in elbow and wrist, pes equinovarus, subluxation of hip and elbow, osteoporosis), the skin (redundant skin on hands and feet leading to deep palmar and plantar creases and ridges, acanthosis nigricans, hyperkeratosis, fine hair, papillomata [facial, laryngeal, axillary, abdominal, cubital, popliteal, anal], multiple pigmented nevi, capillary hemangiomata on the forehead), the central nervous system (developmental delay with an IQ between 47 and 85, speech development delay, seizures, mild brain atrophy, cerebellar atrophy, generalized ventricular dilatation [occasionally requiring ventriculoperitoneal shunting], muscular hypotonia or hypertonia), and the genital region (cryptorchidism, inguinal hernia). Cardiac abnormalities including hypertrophic cardiomyopathy, pulmonary stenosis, atrial and ventricular septal defects, and dysrhythmias have been described. Hepatosplenomegaly and umbilical hernias have been described in some patients. These patients have an increased risk for malignant solid tumors (up ...