Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple-anomaly / cognitive impairment syndrome caused by an abnormality in cholesterol metabolism resulting from deficiency of the enzyme 7-dehydrocholesterol (7-DHC) reductase. It is characterized by prenatal and postnatal growth restriction, microcephaly, moderate-to-severe intellectual disability, and multiple major and minor malformations. The malformations include distinctive facial features, cleft palate, cardiac defects, underdeveloped external genitalia in males, postaxial polydactyly, and 2-3 syndactyly of the toes. The clinical spectrum is wide; individuals with normal development and only minor malformations have been described.

The 17q12 recurrent deletion syndrome is characterized by variable combinations of the three following findings: structural or functional abnormalities of the kidney and urinary tract, maturity-onset diabetes of the young type 5 (MODY5), and neurodevelopmental or neuropsychiatric disorders (e.g., developmental delay, intellectual disability, autism spectrum disorder, schizophrenia, anxiety, and bipolar disorder). Using a method of data analysis that avoids ascertainment bias, the authors determined that multicystic kidneys and other structural and functional kidney anomalies occur in 85% to 90% of affected individuals, MODY5 in approximately 40%, and some degree of developmental delay or learning disability in approximately 50%. MODY5 is most often diagnosed before age 25 years (range: age 10-50 years).

Kabuki syndrome (KS) is characterized by typical facial features (long palpebral fissures with eversion of the lateral third of the lower eyelid; arched and broad eyebrows; short columella with depressed nasal tip; large, prominent, or cupped ears), minor skeletal anomalies, persistence of fetal fingertip pads, mild-to-moderate intellectual disability, and postnatal growth deficiency. Other findings may include: congenital heart defects, genitourinary anomalies, cleft lip and/or palate, gastrointestinal anomalies including anal atresia, ptosis and strabismus, and widely spaced teeth and hypodontia. Functional differences can include: increased susceptibility to infections and autoimmune disorders, seizures, endocrinologic abnormalities (including isolated premature thelarche in females), feeding problems, and hearing loss.

Kleta (2006) reviewed aspects of renal stone disease. Nephrolithiasis and urolithiasis remain major public health problems of largely unknown cause. While disorders such as cystinuria (220100) and primary hyperoxaluria (see 259900) that have nephrolithiasis as a major feature have advanced understanding of the metabolic and physiologic processes of stone formation in general, they have not addressed the etiology of calcium oxalate stone formation, responsible for approximately 75% of urolithiasis cases in humans. Men are affected twice as often as women, but children show no such gender bias. The recurrence rate is also high. In populations of European ancestry, 5 to 10% of adults experience the painful precipitation of calcium oxalate in their urinary tracts. Thorleifsson et al. (2009) noted that between 35 and 65% of hypercalciuric stone formers and up to 70% of subjects with hypercalciuria have relatives with nephrolithiasis, and twin studies have estimated the heritability of kidney stones to be 56%. Genetic Heterogeneity of Calcium Oxalate Nephrolithiasis See also CAON2 (620374), caused by mutation in the OXGR1 gene (606922) on chromosome 13q32.

Congenital anomalies of the kidney and urinary tract (CAKUT) comprise a broad spectrum of renal and urinary tract malformations. CAKUT structural anomalies range from complete renal agenesis (the most severe), to renal hypodysplasia, multicystic kidney dysplasia, duplex renal collecting system, ureteropelvic junction obstruction (UPJO), megaureter, posterior urethral valves (PUV), and vesicoureteral reflux (VUR). Renal abnormalities are observed in close relatives of up to 10% of CAKUT patients, although these are frequently asymptomatic. The phenotype often does not follow classic mendelian inheritance: family members with the same genetic defect may have variable phenotypes, ranging from severe renal insufficiency to asymptomatic anomalies. CAKUT occurs in about 1 in 500 live births, but are severe enough to cause neonatal death in about 1 in 2,000 births. In addition, CAKUT can occur in syndromic disorders in association with other congenital anomalies, such as papillorenal syndrome (120330) (summary by Renkema et al., 2011). Genetic Heterogeneity of Congenital Anomalies of Kidney and Urinary Tract Also see CAKUT2 (143400), caused by mutation in the TBX18 gene (604613) on chromosome 6q14, and CAKUT3 (618270), caused by mutation in the NRIP1 gene (602490) on chromosome 21q.

Hand-foot-genital syndrome (HFGS) is characterized by limb malformations and urogenital defects. Mild-to-severe bilateral shortening of the thumbs and great toes, caused primarily by shortening of the distal phalanx and/or the first metacarpal or metatarsal, is the most common limb malformation and results in impaired dexterity or apposition of the thumbs. Urogenital malformations include abnormalities of the ureters and urethra and various degrees of incomplete müllerian fusion in females, and hypospadias of variable severity with or without chordee in males. Vesicoureteral reflux, recurrent urinary tract infections, and chronic pyelonephritis may occur; fertility is normal.

CHIME syndrome, also known as Zunich neuroectodermal syndrome, is an extremely rare autosomal recessive multisystem disorder clinically characterized by colobomas, congenital heart defects, migratory ichthyosiform dermatosis, mental retardation, and ear anomalies (CHIME). Other clinical features include distinctive facial features, abnormal growth, genitourinary abnormalities, seizures, and feeding difficulties (summary by Ng et al., 2012). The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis. For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).

Sex reversal in an individual associated with a 9p24.3 deletion.

Craniofacial microsomia (CFM) is an autosomal dominant disorder characterized by mandibular hypoplasia, microtia, facial and preauricular skin tags, epibulbar dermoids, and lateral oral clefts, in addition to skeletal and cardiac abnormalities. Inter- and intrafamilial variability has been observed (Timberlake et al., 2021). Hemifacial microsomia is a common birth defect involving the first and second branchial arch derivatives. It typically affects the external ear, middle ear, mandible and temporomandibular joint, muscles of mastication and facial muscles, and other facial soft tissues on the affected side. In some cases, other facial structures, such as the orbit, eye, nose, cranium, or neck, may be involved. Involvement is usually limited to one side, but bilateral involvement is known. In addition to craniofacial anomalies, there may be cardiac, vertebral, and central nervous system defects. The phenotype is highly variable. Most cases are sporadic, but there are rare familial cases that exhibit autosomal dominant inheritance (summary by Poole, 1989 and Hennekam et al., 2010). See also hemifacial microsomia with radial defects (141400) and oculoauriculofrontonasal dysplasia (OAFNS; 601452), which may be part of the OAV spectrum. Another disorder that overlaps clinically with CFM is Townes-Brocks syndrome (TBS; 107480).

Congenital disorder of glycosylation type IIm, or developmental and epileptic encephalopathy-22 (DEE22), is an X-linked dominant severe neurologic disorder characterized by infantile-onset seizures, hypsarrhythmia on EEG, hypotonia, and developmental delay associated with severe intellectual disability and lack of speech. These features are consistent with developmental and epileptic encephalopathy (DEE). Brain malformations usually include cerebral and cerebellar atrophy. Additionally, some patients may have dysmorphic features or coarse facies (Ng et al., 2013; Kodera et al., 2013). For a general discussion of CDGs, see CDG1A (212065) and CDG2A (212066). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350.

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).

GNB1 encephalopathy (GNB1-E) is characterized by moderate-to-severe developmental delay / intellectual disability, structural brain abnormalities, and often infantile hypotonia and seizures. Other less common findings include dystonia, reduced vision, behavior issues, growth delay, gastrointestinal (GI) problems, genitourinary (GU) abnormalities in males, and cutaneous mastocytosis.

Gabriele-de Vries syndrome is characterized by mild-to-profound developmental delay / intellectual disability (DD/ID) in all affected individuals and a wide spectrum of functional and morphologic abnormalities. Intrauterine growth restriction or low birth weight and feeding difficulties are common. Congenital brain, eye, heart, kidney, genital, and/or skeletal system anomalies have also been reported. About half of affected individuals have neurologic manifestations, including hypotonia and gait abnormalities. Behavioral issues can include attention-deficit/hyperactivity disorder, anxiety, autism or autistic behavior, and schizoaffective disorder.

Congenital myopathy-17 (CMYP17) is an autosomal recessive muscle disorder. Affected individuals present at birth with hypotonia and respiratory insufficiency associated with high diaphragmatic dome on imaging. Other features include poor overall growth, pectus excavatum, dysmorphic facies, and renal anomalies in some. The severity of the disorder is highly variable: some patients may have delayed motor development with mildly decreased endurance, whereas others have more severe hypotonia associated with distal arthrogryposis and lung hypoplasia, resulting in early death (summary by Watson et al., 2016 and Lopes et al., 2018). For a discussion of genetic heterogeneity of congenital myopathy, see CMYP1A (117000).

Neurodevelopmental-craniofacial syndrome with variable renal and cardiac abnormalities (NECRC) is an autosomal dominant disorder characterized by dysmorphic craniofacial features associated with mild developmental delay, mildly impaired intellectual development or learning difficulties, speech delay, and behavioral abnormalities. About half of patients have congenital anomalies of the kidney and urinary tract (CAKUT) and/or congenital cardiac defects, including septal defects (Connaughton et al., 2020).

Congenital anomalies of the kidneys and urinary tract (CAKUT) encompasses a spectrum of developmental disorders of the urinary tract that can range from mild vesicoureteral reflux to severe renal agenesis. Other phenotypes include renal duplication, small kidneys, ureteropelvic junction obstruction, hydronephrosis, and renal dysplasia. These abnormalities can result in kidney damage, and possibly renal failure (summary by Vivante et al., 2015). For a discussion of genetic heterogeneity of CAKUT, see 610805.