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.

Supernumerary digits located at the radial side of the hand. Polydactyly (supernumerary digits) involving the thumb occurs in many distinct forms of high variability and severity. Ranging from fleshy nubbins over varying degrees of partial duplication/splitting to completely duplicated or even triplicated thumbs or preaxial (on the radial side of the hand) supernumerary digits.

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.

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.

Fanconi anemia (FA) is characterized by physical abnormalities, bone marrow failure, and increased risk for malignancy. Physical abnormalities, present in approximately 75% of affected individuals, include one or more of the following: short stature, abnormal skin pigmentation, skeletal malformations of the upper and/or lower limbs, microcephaly, and ophthalmic and genitourinary tract anomalies. Progressive bone marrow failure with pancytopenia typically presents in the first decade, often initially with thrombocytopenia or leukopenia. The incidence of acute myeloid leukemia is 13% by age 50 years. Solid tumors – particularly of the head and neck, skin, and genitourinary tract – are more common in individuals with FA.

Craniofacial microsomia is a term used to describe a spectrum of abnormalities that primarily affect the development of the skull (cranium) and face before birth. Microsomia means abnormal smallness of body structures. Most people with craniofacial microsomia have differences in the size and shape of facial structures between the right and left sides of the face (facial asymmetry). In about two-thirds of cases, both sides of the face have abnormalities, which usually differ from one side to the other. Other individuals with craniofacial microsomia are affected on only one side of the face. The facial characteristics in craniofacial microsomia typically include underdevelopment of one side of the upper or lower jaw (maxillary or mandibular hypoplasia), which can cause dental problems and difficulties with feeding and speech. In cases of severe mandibular hypoplasia, breathing may also be affected.\n\nPeople with craniofacial microsomia usually have ear abnormalities affecting one or both ears, typically to different degrees. They may have growths of skin (skin tags) in front of the ear (preauricular tags), an underdeveloped or absent external ear (microtia or anotia), or a closed or absent ear canal; these abnormalities may lead to hearing loss. Eye problems are less common in craniofacial microsomia, but some affected individuals have an unusually small eyeball (microphthalmia) or other eye abnormalities that result in vision loss.\n\nAbnormalities in other parts of the body, such as malformed bones of the spine (vertebrae), abnormally shaped kidneys, and heart defects, may also occur in people with craniofacial microsomia.\n\nMany other terms have been used for craniofacial microsomia. These other names generally refer to forms of craniofacial microsomia with specific combinations of signs and symptoms, although sometimes they are used interchangeably. Hemifacial microsomia often refers to craniofacial microsomia with maxillary or mandibular hypoplasia. People with hemifacial microsomia and noncancerous (benign) growths in the eye called epibulbar dermoids may be said to have Goldenhar syndrome or oculoauricular dysplasia.

Nephrotic syndrome type 11 (NPHS11) is an autosomal recessive disorder of the kidney with onset in the first decade of life. The disorder is progressive and usually results in end-stage renal disease necessitating renal transplantation, although some patients may have a slightly milder phenotype (Miyake et al., 2015). For a general phenotypic description and a discussion of genetic heterogeneity of nephrotic syndrome, see NPHS1 (256300).

Autosomal dominant Robinow syndrome (ADRS) is characterized by skeletal findings (short stature, mesomelic limb shortening predominantly of the upper limbs, and brachydactyly), genital abnormalities (in males: micropenis / webbed penis, hypoplastic scrotum, cryptorchidism; in females: hypoplastic clitoris and labia majora), dysmorphic facial features (widely spaced and prominent eyes, frontal bossing, anteverted nares, midface retrusion), dental abnormalities (including malocclusion, crowding, hypodontia, late eruption of permanent teeth), bilobed tongue, and occasional prenatal macrocephaly that persists postnatally. Less common findings include renal anomalies, radial head dislocation, vertebral abnormalities such as hemivertebrae and scoliosis, nail dysplasia, cardiac defects, cleft lip/palate, and (rarely) cognitive delay. When present, cardiac defects are a major cause of morbidity and mortality. A variant of Robinow syndrome, associated with osteosclerosis and caused by a heterozygous pathogenic variant in DVL1, is characterized by normal stature, persistent macrocephaly, increased bone mineral density with skull osteosclerosis, and hearing loss, in addition to the typical features described above.

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.

Galloway-Mowat syndrome-7 (GAMOS7) is an autosomal recessive disorder characterized by developmental delay, microcephaly, and early-onset nephrotic syndrome (summary by Rosti et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (251300).

Lacrimoauriculodentodigital syndrome-3 (LADD3) is a multiple congenital anomaly disorder characterized by aplasia, atresia or hypoplasia of the lacrimal and salivary systems, cup-shaped ears, hearing loss, and dental and digital anomalies (summary by Milunsky et al., 2006).

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.