MedGen

The FLNB disorders include a spectrum of phenotypes ranging from mild to severe. At the mild end are spondylocarpotarsal synostosis (SCT) syndrome and Larsen syndrome; at the severe end are the phenotypic continuum of atelosteogenesis types I (AOI) and III (AOIII) and Piepkorn osteochondrodysplasia (POCD). SCT syndrome is characterized by postnatal disproportionate short stature, scoliosis and lordosis, clubfeet, hearing loss, dental enamel hypoplasia, carpal and tarsal synostosis, and vertebral fusions. Larsen syndrome is characterized by congenital dislocations of the hip, knee, and elbow; clubfeet (equinovarus or equinovalgus foot deformities); scoliosis and cervical kyphosis, which can be associated with a cervical myelopathy; short, broad, spatulate distal phalanges; distinctive craniofacies (prominent forehead, depressed nasal bridge, malar flattening, and widely spaced eyes); vertebral anomalies; and supernumerary carpal and tarsal bone ossification centers. Individuals with SCT syndrome and Larsen syndrome can have midline cleft palate and hearing loss. AOI and AOIII are characterized by severe short-limbed dwarfism; dislocated hips, knees, and elbows; and clubfeet. AOI is lethal in the perinatal period. In individuals with AOIII, survival beyond the neonatal period is possible with intensive and invasive respiratory support. Piepkorn osteochondrodysplasia (POCD) is a perinatal-lethal micromelic dwarfism characterized by flipper-like limbs (polysyndactyly with complete syndactyly of all fingers and toes, hypoplastic or absent first digits, and duplicated intermediate and distal phalanges), macrobrachycephaly, prominant forehead, hypertelorism, and exophthalmos. Occasional features include cleft palate, omphalocele, and cardiac and genitourinary anomalies. The radiographic features at mid-gestation are characteristic. [from GeneReviews]

Congenital laryngeal (glottic) webs are uncommon, membrane-like structures that extend across the laryngeal lumen near the level of the vocal cords. They are thought to result from incomplete resorption of an epithelial layer that normally obliterates the developing laryngeal opening at about the sixth week of embryologic life. This layer is usually completely eliminated by the tenth week. Most laryngeal webs occur at the glottic level and affect the vocal cords. More than 90% are located anteriorly and extend toward the arytenoids. While affected persons may have onset of manifestations at any age, with hoarse or weak voice and frequent upper respiratory infections, they usually manifest the condition as infants, with respiratory distress, stridor, and an unusual cry (Strakowski et al., 1988; Singh et al., 2009). [from OMIM]

An abnormal appearance of the long bones with resemblance to a dumbbell, a short bar with a weight at each end. That is, the long bone is shortened and displays flaring (widening) of the metaphyses. [from HPO]

Classic ataxia-telangiectasia (A-T) is characterized by progressive cerebellar ataxia beginning between ages one and four years, oculomotor apraxia, choreoathetosis, telangiectasias of the conjunctivae, immunodeficiency, frequent infections, and an increased risk for malignancy, particularly leukemia and lymphoma. Individuals with A-T are unusually sensitive to ionizing radiation. Non-classic forms of A-T have included adult-onset A-T and A-T with early-onset dystonia. [from GeneReviews]

Synostosis (bony fusion) involving one or more bones of the tarsus (calcaneus, talus, cuboid, navicular, cuneiiform bones). [from HPO]