A rare branchial arches and limb primordia development disorder with characteristics of variable degrees of uni or bilateral craniofacial malformation and radial defects that result in extremely variable phenotypic manifestations. Characteristic features include low postnatal weight, short stature, vertebral defects, hearing loss, and facial dysmorphism (including facial asymmetry, external, middle and inner ear malformations, orofacial clefts, and mandibular hypoplasia). These features are invariably associated with radial defects, such as preaxial polydactyly, thumb and/or radius hypoplasia/agenesis, or triphalangeal thumb. Cardiac, pulmonary, renal, and central nervous system involvement has also been reported.

Nager syndrome is the prototype for a group of disorders collectively referred to as the acrofacial dysostoses (AFDs), which are characterized by malformation of the craniofacial skeleton and the limbs. The major facial features of Nager syndrome include downslanted palpebral fissures, midface retrusion, and micrognathia, the latter of which often requires the placement of a tracheostomy in early childhood. Limb defects typically involve the anterior (radial) elements of the upper limbs and manifest as small or absent thumbs, triphalangeal thumbs, radial hypoplasia or aplasia, and radioulnar synostosis. Phocomelia of the upper limbs and, occasionally, lower-limb defects have also been reported. The presence of anterior upper-limb defects and the typical lack of lower-limb involvement distinguishes Nager syndrome from Miller syndrome (263750), another rare AFD; however, distinguishing Nager syndrome from other AFDs, including Miller syndrome, can be challenging (summary by Bernier et al., 2012).

Holt-Oram syndrome (HOS) is characterized by upper-limb defects, congenital heart malformation, and cardiac conduction disease. Upper-limb malformations may be unilateral, bilateral/symmetric, or bilateral/asymmetric and can range from triphalangeal or absent thumb(s) to phocomelia. Other upper-limb malformations can include unequal arm length caused by aplasia or hypoplasia of the radius, fusion or anomalous development of the carpal and thenar bones, abnormal forearm pronation and supination, abnormal opposition of the thumb, sloping shoulders, and restriction of shoulder joint movement. An abnormal carpal bone is present in all affected individuals and may be the only evidence of disease. A congenital heart malformation is present in 75% of individuals with HOS and most commonly involves the septum. Atrial septal defect and ventricular septal defect can vary in number, size, and location. Complex congenital heart malformations can also occur in individuals with HOS. Individuals with HOS with or without a congenital heart malformation are at risk for cardiac conduction disease. While individuals may present at birth with sinus bradycardia and first-degree atrioventricular (AV) block, AV block can progress unpredictably to a higher grade including complete heart block with and without atrial fibrillation.

TBC1D24-related disorders comprise a continuum of features that were originally described as distinct, recognized phenotypes: DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures). Profound sensorineural hearing loss, onychodystrophy, osteodystrophy, intellectual disability / developmental delay, and seizures. Familial infantile myoclonic epilepsy (FIME). Early-onset myoclonic seizures, focal epilepsy, dysarthria, and mild-to-moderate intellectual disability. Progressive myoclonus epilepsy (PME). Action myoclonus, tonic-clonic seizures, progressive neurologic decline, and ataxia. Early-infantile epileptic encephalopathy 16 (EIEE16). Epileptiform EEG abnormalities which themselves are believed to contribute to progressive disturbance in cerebral function. Autosomal recessive nonsyndromic hearing loss, DFNB86. Profound prelingual deafness. Autosomal dominant nonsyndromic hearing loss, DFNA65. Slowly progressive deafness with onset in the third decade, initially affecting the high frequencies.

IVIC syndrome (IVIC) is an autosomal dominant disorder characterized by upper limb anomalies (radial ray defects, carpal bone fusion), extraocular motor disturbances, and congenital bilateral nonprogressive mixed hearing loss. More variable features include heart involvement, mild thrombocytopenia and leukocytosis (before age 50), shoulder girdle hypoplasia, imperforate anus, kidney malrotation, and rectovaginal fistula (summary by Paradisi and Arias, 2007).

SALL4-related disorders include Duane-radial ray syndrome (DRRS, Okihiro syndrome), acro-renal-ocular syndrome (AROS), and SALL4-related Holt-Oram syndrome (HOS) – three phenotypes previously thought to be distinct entities. DRRS is characterized by uni- or bilateral Duane anomaly and radial ray malformation that can include thenar hypoplasia and/or hypoplasia or aplasia of the thumbs, hypoplasia or aplasia of the radii, shortening and radial deviation of the forearms, triphalangeal thumbs, and duplication of the thumb (preaxial polydactyly). AROS is characterized by radial ray malformations, renal abnormalities (mild malrotation, ectopia, horseshoe kidney, renal hypoplasia, vesicoureteral reflux, bladder diverticula), ocular coloboma, and Duane anomaly. Rarely, pathogenic variants in SALL4 may cause clinically typical HOS (i.e., radial ray malformations and cardiac malformations without additional features).

Laurin-Sandrow syndrome (LSS) is an autosomal dominant disorder characterized by polysyndactyly of hands and feet, mirror image duplication of feet, and nasal defects (hypoplastic alae nasi, short columella), in connection with absent patella and duplicated fibula (summary by Lohan et al., 2014).

Syndrome with characteristics of a combination of distal limb abnormalities (syndactyly of all fingers and toes, preaxial polydactyly in the feet and/or hands) and upper sternum malformations. It has been described in 22 patients from a six-generation Turkish family. It is transmitted as an autosomal dominant trait and the causative gene is located at 7q36.

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

Craniosynostosis is a primary abnormality of skull growth involving premature fusion of the cranial sutures such that the growth velocity of the skull often cannot match that of the developing brain. This produces skull deformity and, in some cases, raises intracranial pressure, which must be treated promptly to avoid permanent neurodevelopmental disability (summary by Fitzpatrick, 2013). For a discussion of genetic heterogeneity of craniosynostosis, see CRS1 (123100).

A multiple malformation syndrome in which mandibulofacial dysostosis and severe limb reduction defects are associated with complex malformations of different organs and systems especially the central nervous system, urogenital tract, heart, and lungs. The mandibulofacial defect causes death by respiratory distress. Limb reduction is severe and includes shoulder and pelvis hypoplasia, phocomelia with humerus hypoplasia, absent radius and ulna, complete absence of long bones of the legs, and various hand anomalies, predominantly preaxial reduction. These infants also show facial dysmorphism and ear anomalies. The condition is a rare with an autosomal recessive mode of inheritance. The prognosis is poor and this condition leads to death in utero or shortly after birth.

This syndrome has characteristics of triphalangeal thumbs and brachydactyly of the hands. Ectrodactyly of the feet and, more rarely, ectrodactyly of the hands were also reported in some family members. Transmission is autosomal dominant.

Say-Field-Coldwell syndrome is characterized by triphalangeal thumbs, brachydactyly, camptodactyly, recurrent dislocation of the patellas and relatively short stature. It has been described in a mother and her three daughters.

Tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome is a rare, genetic dysostosis syndrome, with marked inter- and intra-familial variation, typically characterized by triphalangeal thumbs, hand and/or foot polysyndactyly and/or absent/hypoplastic tibiae (associated with duplication of fibulae in some cases), although isolated triphalangeal thumbs have also been reported. It is often accompanied with remarkable short stature and additional features may include radio-ulnar synostosis and hand oligodactyly, as well as abnormal carpal and metatarsal bones.

Syndactyly type IV (SDTY4) is characterized by complete syndactylism of all the fingers accompanied by polydactyly and cup-shaped hands due to flexion of the fingers (summary by Sato et al., 2007).

A limb malformation syndrome, where the thumb is replaced by one or two triphalangeal digits with dermatoglyphic pattern specific of the index finger. Two forms of PPD3 have been described, unilateral and bilateral. There have been no further descriptions in the literature since 1962.

Diamond-Blackfan anemia (DBA) is characterized by a profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50%, and growth deficiency in 30% of affected individuals. The hematologic complications occur in 90% of affected individuals during the first year of life. The phenotypic spectrum ranges from a mild form (e.g., mild anemia or no anemia with only subtle erythroid abnormalities, physical malformations without anemia) to a severe form of fetal anemia resulting in nonimmune hydrops fetalis. DBA is associated with an increased risk for acute myelogenous leukemia (AML), myelodysplastic syndrome (MDS), and solid tumors including osteogenic sarcoma.

The DDOD syndrome is characterized by autosomal dominant inheritance of congenital deafness and onychodystrophy. Conical, hypoplastic teeth is also a feature (Robinson et al., 1962). See also DOOR syndrome (220500), an autosomal recessive disorder, which includes congenital deafness, onychodystrophy, osteodystrophy, and mental retardation.

Diamond-Blackfan anemia (DBA) is characterized by a profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50%, and growth deficiency in 30% of affected individuals. The hematologic complications occur in 90% of affected individuals during the first year of life. The phenotypic spectrum ranges from a mild form (e.g., mild anemia or no anemia with only subtle erythroid abnormalities, physical malformations without anemia) to a severe form of fetal anemia resulting in nonimmune hydrops fetalis. DBA is associated with an increased risk for acute myelogenous leukemia (AML), myelodysplastic syndrome (MDS), and solid tumors including osteogenic sarcoma.

Split-hand/foot malformation (SHFM) is a limb malformation involving the central rays of the autopod and presenting with syndactyly, median clefts of the hands and feet, and aplasia and/or hypoplasia of the phalanges, metacarpals, and metatarsals. Some patients with SHFM1 have been found to have mental retardation, ectodermal and craniofacial findings, orofacial clefting (Elliott and Evans, 2006), and neurosensory hearing loss (Tackels-Horne et al., 2001). Genetic Heterogeneity of Split-Hand/Foot Malformation Additional SHFM loci include SHFM2 (313350) on chromosome Xq26; SHFM3 (246560), caused by duplication of chromosome 10q24; SHFM4 (605289), caused by mutation in the TP63 gene (603273) on chromosome 3q28; SHFM5 (606708) on chromosome 2q31; and SHFM6 (225300), caused by mutation in the WNT10B gene (601906) on chromosome 12q13. Also see SHFM1D (220600) for a form of SHFM1 with deafness that may be caused by homozygous mutation in the DLX5 gene (600028). Associations Pending Confirmation For discussion of a possible association between split-hand/foot malformation and variation in the EPS15L1 gene, see 616826.0001.

A form of triphalangeal thumb that cannot be placed opposite the fingers of the same hand.

Diamond-Blackfan anemia (DBA) is characterized by a profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50%, and growth deficiency in 30% of affected individuals. The hematologic complications occur in 90% of affected individuals during the first year of life. The phenotypic spectrum ranges from a mild form (e.g., mild anemia or no anemia with only subtle erythroid abnormalities, physical malformations without anemia) to a severe form of fetal anemia resulting in nonimmune hydrops fetalis. DBA is associated with an increased risk for acute myelogenous leukemia (AML), myelodysplastic syndrome (MDS), and solid tumors including osteogenic sarcoma.

A rare, genetic, chromosomal anomaly syndrome resulting from partial duplication of the long arm of chromosome 2 characterized by congenital pendular nystagmus associated with bilateral cutaneous syndactyly between the third and fourth fingers.

Diamond-Blackfan anemia (DBA) is characterized by a profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50%, and growth deficiency in 30% of affected individuals. The hematologic complications occur in 90% of affected individuals during the first year of life. The phenotypic spectrum ranges from a mild form (e.g., mild anemia or no anemia with only subtle erythroid abnormalities, physical malformations without anemia) to a severe form of fetal anemia resulting in nonimmune hydrops fetalis. DBA is associated with an increased risk for acute myelogenous leukemia (AML), myelodysplastic syndrome (MDS), and solid tumors including osteogenic sarcoma.

VATER is a mnemonically useful acronym for the nonrandom association of vertebral defects (V), anal atresia (A), tracheoesophageal fistula with esophageal atresia (TE), and radial or renal dysplasia (R). This combination of associated defects was pointed out by Quan and Smith (1972). Nearly all cases have been sporadic. VACTERL is an acronym for an expanded definition of the association that includes cardiac malformations (C) and limb anomalies (L). The VACTERL association is a spectrum of various combinations of its 6 components, which can be a manifestation of several recognized disorders rather than a distinct anatomic or etiologic entity (Khoury et al., 1983). Also see VATER/VACTERL association with hydrocephalus (VACTERL-H; 276950) and VACTERL with or without hydrocephalus (VACTERLX; 314390).

Townes-Brocks syndrome (TBS) is characterized by the triad of imperforate anus (84%), dysplastic ears (87%; overfolded superior helices and preauricular tags; frequently associated with sensorineural and/or conductive hearing impairment [65%]), and thumb malformations (89%; triphalangeal thumbs, duplication of the thumb [preaxial polydactyly], and rarely hypoplasia of the thumbs). Renal impairment (42%), including end-stage renal disease (ESRD), may occur with or without structural abnormalities (mild malrotation, ectopia, horseshoe kidney, renal hypoplasia, polycystic kidneys, vesicoutereral reflux). Congenital heart disease occurs in 25%. Foot malformations (52%; flat feet, overlapping toes) and genitourinary malformations (36%) are common. Intellectual disability occurs in approximately 10% of individuals. Rare features include iris coloboma, Duane anomaly, Arnold-Chiari malformation type 1, and growth retardation.

Developmental and epileptic encephalopathy-80 (DEE80) is an autosomal recessive neurologic disorder characterized by the onset of refractory seizures in the first year of life. Patients have severe global developmental delay and may have additional variable features, including dysmorphic or coarse facial features, distal skeletal abnormalities, and impaired hearing or vision. At the cellular level, the disorder is caused by a defect in the synthesis of glycosylphosphatidylinositol (GPI), and thus affects the expression of GPI-anchored proteins at the cell surface (summary by Murakami et al., 2019). For a discussion of genetic heterogeneity of DEE, see 308350. For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).

Zimmermann-Laband syndrome-3 (ZLS3) is characterized by developmental delay, intellectual disability, coarse face, gingival hyperplasia, and nail hypoplasia/aplasia (Bauer et al., 2019). For a general phenotypic description and a discussion of genetic heterogeneity of Zimmermann-Laband syndrome, see ZLS1 (135500).

Lacrimoauriculodentodigital syndrome-1 (LADD1) is a multiple congenital anomaly disorder mainly affecting lacrimal glands and ducts, salivary glands and ducts, ears, teeth, and distal limb segments (summary by Rohmann et al., 2006). Genetic Heterogeneity of Lacrimoauriculodentodigital Syndrome LADD syndrome-2 (LADD2; 620192) is caused by mutation in the FGFR3 gene (134934) on chromosome 4p16, and LADD syndrome-3 (LADD3; 620193) is caused by mutation in the FGF10 gene, an FGFR ligand, on chromosome 5p12.

Triphalangeal thumb-polysyndactyly syndrome (TPT-PS) is a hand-foot malformation characterized by triphalangeal thumbs and pre- and postaxial polydactyly, isolated syndactyly or complex polysyndactyly.