10 – Congenital Abnormalities and Syndromes

10 Congenital Abnormalities and Syndromes

Katherine R. Gentry and Anne M. Lynn

This chapter is dedicated to presenting an approach to evaluating neonates with congenital anomalies and a review of commonly presenting syndromes seen in the nursery. There is likely to be significant overlap with other chapters in this book and cross-referencing is recommended. Following a discussion of some of the more common syndromes seen in neonates, we have included a table of additional syndromes not covered in the text, with particular emphasis on features of the airway and/or the presence of congenital cardiac disease (see Table 10.1).

Table 10.1 Syndromes, include those not covered by this chapter, with features of the airway and/or the presence of congenital cardiac disease

Syndrome	Airway/respiratory concerns	Cardiac disease (incidence, if known)	Other features of note
Chromosomal
Trisomy 21	Large tongue, small trachea, C-spine instability	AV canal, ASD, VSD (50 percent) ToF (8 percent)	See text
Trisomy 13 (Patau syndrome)	Cleft lip and palate, choanal atresia Facemask ventilation may be impossible	90 percent: ASD, VSD, coarctation, bicuspid aortic valve, dextroversion	Associated with midline defects High mortality in first six months of life
Trisomy 18 (Edwards syndrome)	Microstomia, micrognathia, high arched palate	ASD, VSD, PDA, PS, coarctation	High mortality in first year of life
3 p duplication	Large mouth, cleft lip and palate, choanal atresia	ToF, VSD, hypoplastic heart, TGA	>50 percent die in first two years of life
4 p duplication (trisomy 4p)	Cleft lip and palate, macroglossia, microglossia	Congenital heart disease often present: ASD, VSD	Recurrent pulmonary aspiration → chronic respiratory disease Life expectancy approximately two years
Trisomy 8 mosaicism	Short neck, microretrognathia, difficult mask fit	Cardiac septal defects and great vessel abnormalities	Mental deficiency, seizures, Factor VIII deficiency
Trisomy 9	Short neck, ankyloglossia, microretrognathia	ASD, VSD, PDA, valve abnormalities, DORV	Severe mental deficiency Death in infancy or early childhood IV access difficult
5p Cri du Chat	Microcephaly, occasional micrognathia, long epiglottis, difficult DL	CHD in 33 percent: PDA, ASD, VSD, or PS	Developmental delay, aspiration risk Life expectancy early childhood
22q11.2 deletion DiGeorge	Midface hypoplasia, microretrognathia, high arched palate, tracheal anomalies	IAA (30–56 percent), ToF (20–30 percent), truncus arteriosus (13–30 percent), right aortic arch (14–26 percent), VSD (8–25 percent), DORV, TGA, PS, R infundibular stenosis	Hypocalcemia (hypoplasia of parathyroid), immunodeficiency (thymic aplasia)
22q11.2 deletion velocardiofacial	Prominent nose, retrognathia, high arched palate (mandibular abnormalities appearing like Robin Sequence)	R aortic arch (50 percent), VSD (75 percent), ToF (20 percent), abnormal carotid and L subclavian arteries	Hypothyroidism, hypocalcemia, T-cell immunodeficiency, thymic hypoplasia
22q11 conotruncal anomaly face (variant of DiGeorge)	Cleft lip/palate microglossia	ToF, PA, DORV, TA, aortic arch abnormalities	Thymic and parathyroid hypoplasia, with immunodeficiency and neonatal hypocalcemia, anal atresia, abdominal hernias
CHARGE	Midface hypoplasia, micrognathia, anterior larynx, microstomia, choanal atresia, laryngomalacia, subglottic stenosis	Cardiac defects in 80 percent: ASD, VSD, AV canal, conotruncal malformations, HLHS, PS, coarctation	Cranial nerve dysfunction increases aspiration risk; TEF/EA in 20 percent, see text.
Noonan	Micrognathia, dental malocclusion, short webbed neck Can have atlantoaxial instability	Cardiac defects in 50 percent: PS, hypertrophic cardiomyopathy, ASD, ToF, AV canal, coarctation	Coagulopathy: Factor XI deficiency, thrombocytopenia, other factor deficiencies
Prader–Willi (Neonatal)	None in infancy	None in infancy	Hypotonia, possible history of aspiration, pneumonia
Tuberous sclerosis (TSC-1: chrom 9) (TSC-2: chrom 16)	Oral and laryngeal tumors possible	Cardiac rhabdomyosarcoma	Neurodegenerative Skin: adenoma sebaceum, angiofibromas Neurologic: seizures, obstructive hydrocephalus
Turner syndrome	Short webbed neck, micrognathia	Coarctation of the aorta, dissecting aortic aneurysm, VSD, ASD, dextrocardia, bicuspid AV, HLHS	Infantile presentation: lymphedema
Williams Beuren syndrome	Mandibular hypoplasia	Supravalvar aortic stenosis can lead to sudden death on induction Other cardiac anomalies also possible (see text)	Infantile hypercalcemia Mild mental retardation but normal language development
Mucopolysaccharidoses	Coarse facies make mask fit difficult Thick tongue and stiff neck complicate DL and intubation	Valve thickening, systolic and diastolic dysfunction, arteriosclerosis	Features develop over time as GAGs accumulate (see text)
Endocrine
Beckwith–Wiedemann	Large tongue, maxillary hypoplasia, large size	Cardiomyopathy, cardiac hamartomas, or other congenital heart disease has been described	Severe hypoglycemia in newborn period (see text)
Congenital adrenal hyperplasia syndromes	None	None	Impaired synthesis of cortisol or aldosterone from cholesterol, due to enzymatic defects 21-hydroxylase deficiency responsible for 90 percent of cases Phenotype includes virilization (ambiguous genitalia) ± salt wasting
Immunologic
DiGeorge (see above)
Neonatal lupus erythematosus	None	Congenital heart disease in ~50 percent (10 percent both cutaneous and cardiac manifestations) Complete heart block, PDA, VSD, TGA, ASD coarctation, ToF Pacemaker required in ~ 1/3 of infants with neonatal lupus	Skin lesions in ~50 percent, (“raccoon eyes” generalized, non-scaling, erythematous) disappear at ~6 months of age Occurs in infants of mothers with SLE, resulting from placental transfer of autoantibodies
Metabolic
Mitochondrial DNA deletion syndromes: • Pearson • Kearns–Sayre (KSS) • Leigh (LS)	Risk of postoperative respiratory failure due to neuromuscular weakness (LS, KSS)	Heart block and/or cardiomyopathy can occur (KS)	Pearson: infantile disease with sideroblastic anemia and dysfunction of the exocrine pancreas (→ steatorrhea) – often fatal LS: psychomotor delay or regression presenting in infancy KS: presents in childhood *Avoid lactated Ringer’s and large doses of propofol. Maintain normothermia, normocarbia, and euglycemia. Minimal fasting period, give IV dextrose
Smith Lemli Opitz	Micrognathia, difficult DL	Heart defects in >40 percent: AV canal, TGA, anomalous pulmonary drainage, ToF, VSD	Pulmonary hypoplasia, aspiration risk, hypotonia Multi-organ failure in first week of life due to defective cholesterol production
Skin, muscle, connective tissue
Epidermolysis bullosa	Precautions to minimize mucosal and skin trauma	None	See text
Ehlers–Danlos: encompasses a number of inherited connective tissue disorders	Risk of airway trauma/bruising with any invasive technique. Risk of TMJ dislocation, C-spine subluxation	Valvular insufficiency, conduction system defects	Risk of excessive bleeding: have adequate venous access, blood products available
Marfan syndrome (early-onset form presents in infancy)	Micrognathia, potential TMJ dislocation	Severe cardiac valve insufficiency (MV prolapse common), aortic root dilatation	Multiple systems affected including: eyes, skin, skeletal system, cardiovascular system
Central core myopathy	Occasional mandibular hypoplasia Avoid succinylcholine for intubation	Evaluate for cardiomyopathy and valvular pathology	High susceptibility to MH
King Denborough syndrome	High arched or cleft palate, micrognathia, webbed neck, crowded teeth	Cardiac disease unusual, but should be investigated.	Noonan-like features in infancy, high MH susceptibility
Myotonia congenita • Becker disease • Thompsen disease	No airway anomalies	No cardiac involvement	Thompsen disease presents in infancy to early childhood: see inability to relax muscles, blepharospasm, diffuse muscular hypertrophy Possible MH risk Do not use succinylcholine to avoid fasciculation-induced myotonia Response to nondepolarizing agents normal Pain with propofol can also precipitate myotonia
Myotonic dystrophy •Types I, II	Aspiration risk due to dysphagia, gastric distention Muscle weakness may cause postoperative respiratory failure	Cardiac conduction defects in 90 percent, cardiomyopathy or valvular pathology possible Degree of cardiac disease does not correlate with severity of muscle disease	Pain and shivering can incite a myotonic reaction No succinylcholine Normal response to nondepolarizing agents Temperature maintenance important
Spinal muscular atrophy I (Werndig Hoffman)	Postoperative respiratory failure serious risk, aspiration risk	–	Presents before three months
SMA II	As above	–	Presents between 3–18 months
Skeletal/musculoskeletal
Arthrogryposis	Difficult DL if TMJ or C-spine involved	Rare	Difficult IV access (see text)
Freeman Sheldon	Small puckered mouth, high arched palate, small mandible	Not typical	Arthrogryposis type IIA Thought to involve fibrous replacement of muscle fibers → possible myopathy Masseter spasm, hyperpyrexia, and tachycardia reported after GA
Multiple pterygium	Diff DL if oral, head, neck involvement; LMA has been successful	Rare	Restrictive lung disease
Klippel Feil	Difficult DL with C-spine limited motion	CHD, usually VSD	See text
VACTERL	TE fistula	CHD common	See text
Osteogenesis imperfecta	Fragile teeth, risk for mandibular fracture so gentle DL	Rare aortic root dilation, MV prolapse	Four types – type 1 most common: blue sclerae, fragile bones, teeth, hearing loss Hyperthermia with anesthesia, not thought to be MH
Jeune syndrome	Small larynx, reduce ETT size	Possible pulmonary hypertension from restrictive lung disease	Hypoplastic lungs, stiff chest wall so low ventilator press Renal cysts – check renal function Postoperative ventilation possible
Robinow syndrome	Possible micrognathia, with difficult DL	CHD – RV outflow obstruction	“Fetal Face S”
Thrombocytopenia with absent radius	Avoid nasal ETT/NG due to low platelet counts	CHD, usually ToF or ASD	Absent radii, decreased platelet count (decreased megakaryocytes)
Craniosynostosis
Antley–Bixler	Choanal atresia, possible need for tracheostomy	Rare	Trapezoidocephaly, eye protection important
Apert	Difficult DL, abnormal trachea	CHD 10 percent – PS, VSD, overriding aorta	Syndactyly – possible difficult IV (see text)
Carpenter	High arch palate, hypoplastic mandible – difficult DL	CHD 50 percent – ASD, VSD, PDA, ToF, TGA	Possible ICP elevation (see text)
Crouzon	Hypoplastic midface		See text
Saethre Chotzen	Occasional C-spine fusion – difficult DL		Possible increased ICP
Kleeblattschaedal	–	–	Cloverleaf skull Eye care important Possible risk for ICP
Other craniofacial
Robin Sequence	Micrognathia, cleft palate, glossoptosis. Obstructive apnea, possible difficult facemask and laryngoscopy Must plan ahead for airway management.	Not typical	May be seen with other syndromes, such as Stickler, Cornelia de Lange, Hallerman-Streiff, or femoral hypoplasia syndromes
Treacher Collins	Malar and mandibular hypoplasia, cleft palate, wide mouth	Cardiac defects possible
Goldenhar	Facial asymmetry, mandibular hypoplasia, unilateral hypoplasia of palate and tongue Possible C1–C2 subluxation	Frequently associated: VSD, ASD, PDA, ToF, coarctation of the aorta	Arnold–Chiari malformation, encephalocele, spina bifida, hydrocephalus
Nager syndrome	Malar hypoplasia, maxiallary and mandibular hypoplasia, posteriorly displaced tongue, cleft lip and palate, laryngeal hypoplasia, absent epiglottis	Not typical	Upper limb malformation always present: hypoplastic or aplastic thumb, to absent radius. Cervical spine deformities frequent
Other anatomical
Bladder exstrophy	None	Not typical, but ductus arteriosus may still be open during first stage repair if performed in first few days of life	Midline structures in lower abdomen fail to fuse Ranges from simple epispadias to cloacal exstrophy exposing bladder and rectum
Pentalogy of Cantrell	None	ASD, VSD, ToF	(1) Midline supraumbilical abdominal defect, (2) Sternal defect (3) Diaphragmatic pericardium deficiency (4) Anterior diaphragm deficiency (5) Congenital cardiac disease
Prune Belly syndrome	No difficult airway association Lack of abdominal muscles may complicate respiratory function pre- and postoperatively	10 percent incidence of heart disease: PDA, ASD, VSD, ToF	(1) Abdominal wall muscular deficiency (2) Urinary tract dilatation (3) Cryptorchidism
Sturge Weber	Facial deformation may make facemask fit difficult. Possible hemangioma of oro- or posterior pharynx Avoid nasotracheal intubation due to increased vascularity	Cardiac malformations possible including coarctation of the aorta	Neurologic: seizures, intracranial calcifications, arachnoid hemangiomas Skin: hemangiomas (port-wine stain) on the face Eyes: coloboma, glaucoma, enlarged globe with choroidal calcification
PHACES	Possible hemangioma in airway Large “plaque-like” facial hemangioma, usually unilateral, in V1 distribution	Cardiac disease in ~1/3 of patients: coarctation of the aorta most common, PDA, ASD, VSD, aberrancies of subclavian artery takeoff	Posterior fossa brain malformations Hemangiomas of face Arterial abnormalities Cardiac anomalies Eye abnormalities Sternal clefting or supraumbilical raphe

Cardiac malformations: ASD, atrial septal defect; AV canal, atrioventricular canal; DORV, double outlet right ventricle.; HLHS, hypoplastic left heart syndrome; IAA, interrupted aortic arch; PDA, patent ductus arteriosus; PS, pulmonary stenosis; TA, tricuspid atresia; TGA, transposition of the great arteries; ToF, Tetralogy of Fallot; VSD, ventricular septal defect.

Other: DL, direct laryngoscopy; EA, esophageal atresia; ETT, endotracheal tube; GAGs, glycosaminoglycans; ICP, intracranial pressure; NG, nasogastric; TEF, tracheoesophageal fistula; TMJ, temporomandibular joint.

Chromosomal and Genetic Abnormalities

Trisomy 21 (T21, Down Syndrome). A genetic syndrome resulting from an extra copy of chromosome 21, either through maternal nondisjunction in meiosis I (>90 percent of cases), chromosomal translocation, or abnormal mitosis resulting in mosaicism.

Incidence: T21 is the most common chromosomal abnormality, with an incidence of about 1:700 live births [1].

Diagnosis: Prenatal diagnosis can be made via cell-free DNA screening for fetal aneuploidy, chorionic villus sampling, or amniocentesis. After birth, diagnosis is based upon clinical features and karyotyping.

Clinical features: Features found in the neonate include a flat facial profile, slanted palpebral fissures, anomalous ears, hypotonia, poor Moro reflex, midphalangeal dysplasia of the fifth finger, a transverse palmar crease, excessive skin at nape of neck, hyperflexibility of joints, and dysplasia of the pelvis [2]. Features involving the airway include: protruding tongue (appears large relative to the hypoplastic midface), subglottic stenosis and narrow tracheal diameter, and obstructive sleep apnea [3,4]. Greater than 40 percent of children with Trisomy 21 have a cardiac defect; atrioventricular canal defects, patent ductus arteriosus, and Tetralogy of Fallot (ToF) are the most common. Patients have immune deficiency and an increased risk of leukemia, including congenital leukemia, which develops within the first three years of life. The skin can be dry and coarse.

Anesthetic considerations: Careful assessment of respiratory and cardiac status is vital. Prepare for a potentially difficult airway due to relative macroglossia, small hypopharynx, and precautions in the case of an unstable cervical spine. A smaller-sized endotracheal tube (ETT) than predicted by age may be indicated due to the risk of subglottic stenosis [3]. Similar considerations apply when planning a nasal tube, as the nasal passages may be smaller. IV access may be difficult, and sterile technique for placement is recommended due to immune suppression. Anesthetic management will be dictated by the presence and status of cardiac disease [1].

Pharmacologic and other considerations: Atropine may cause pronounced mydriasis and tachycardia. High concentrations of sevoflurane, i.e., during inhalational induction, may precipitate bradycardia [5].

22q11 Deletions. The 22q11.2 deletions include a spectrum of features including congenital heart disease, hypocalcemia, immune deficiency, palate abnormalities, and abnormal facies. DiGeorge syndrome will be described as a representative example.

DiGeorge is a genetic syndrome with varied phenotypes, most commonly including cardiac outflow tract obstruction, hypoparathyroidism with hypocalcemia, and immune defects due to thymic hypoplasia.

Incidence: 22q11 deletions occur in 1:3000–1:5000 live births. DiGeorge syndrome involves a monoallelic microdeletion at 22q11.2 (DiGeorge syndrome critical region [DGCR]). It is the most frequent gene deletion and, after trisomy 21, the second most common genetic cause of congenital heart disease. Males and females are equally affected [6].

Diagnosis: Thymic aplasia may be noted during cardiac surgery. This, plus clinical findings (described below), make the diagnosis. CD4+ counts, karyotyping, and fluorescent in situ hybridization (FISH) using probes from within the deletion segment are confirmatory. Abnormal migration of neural crest cells in the fourth week of gestation affects the development of the third and fourth pharyngeal pouches, leading to cardiac defects, abnormal or absent thymus, and hypoparathyroidism [6].

Clinical features: Neonatal hypocalcemia, cardiac defects, and recurrent infections are the hallmarks of neonatal disease. Hypocalcemia results from parathyroid hypoplasia, and may present as tetany or seizures. Associated cardiac malformations include ToF, type B interrupted aortic arch, truncus arteriosus, double outlet right ventricle, transposition of the great arteries, and ventriculo-septal defects, among others. Immune dysfunction begins in the first six months of life. In up to 60 percent of patients, craniofacial anomalies are present. These include small dysplastic ears, hypertelorism, downward-slanted palpebral fissures, a cupid-bow mouth, cleft palate, midface hypoplasia, micrognathia, and retrognathia. Anomalies of the airway and esophagus can be associated, such as tracheoesophageal fistula, and laryngo-, tracheo-, or bronchomalacia. Hydronephrosis or nephrocalcinosis can be seen [1,6].

Anesthetic considerations: Assess cardiac anatomy and function with echocardiography. Anticipate possible difficult intubation. Check CBC including lymphocyte count, and electrolytes with kidney function; monitor calcium levels throughout the case. Use sterile technique due to immune compromise. If giving blood products, only use CMV-negative, irradiated products (Graft Versus Host Disease [GVHD] can result from donor T-lymphocytes attacking the host’s cells; irradiation reduces this risk) [1].

Pharmacologic and other considerations: Exercise caution using drugs with renal excretion in the setting of kidney disease; avoid cardio-depressive medications; consider antibiotic prophylaxis needs.

Further reference: GeneReviews® – www.ncbi.nlm.nih.gov/books/NBK1523.

Williams-Beuren Syndrome (WBS; 7q11.23 deletion). Growth retardation, cardiovascular anomalies, with characteristic facial appearance and personality are features of this hemizygous continuous gene deletion syndrome.

Incidence: The incidence of WBS has been estimated at 1:20 000–1:50 000 live births [7,8]. Prevalence estimates range from 1:7500–1:20 000 [9].

Diagnosis: A contiguous deletion within the Williams Beuren syndrome critical region (WBSCR), which includes the elastin gene, is present in 99 percent of individuals with the diagnosis. FISH or deletion/duplication testing can detect this deletion.

Clinical features: Distinctive facial features, cardiovascular disease, connective tissue abnormalities, endocrine disorders, and intellectual disability (mild) are hallmarks of the disease. The characteristic “elfin facies” includes a broad forehead, short nose with a broad tip, a wide mouth with full lips, and large cheeks. Mandibular hypoplasia and dental abnormalities may be present. Elastin arteriopathy underlies cardiovascular disease; supravalvular aortic stenosis (SVAS), peripheral pulmonary stenosis, coronary disease, mitral valve prolapse, coarctation of the aorta, and patent ductus arteriosus have been reported. Intracardiac lesions such as ToF and ventricular septal defects also occur. Connective tissue abnormalities that might be present in the neonate include hoarse voice/cry, inguinal and umbilical hernias, plus joint and skin laxity. Hypercalcemia is common in the neonate, which can lead to nephrocalcinosis [10].

Anesthetic considerations: Patients with WBS have an increased risk of cardiac arrest and sudden death under anesthesia. The incidence of sudden death in WBS (due to all causes), has been estimated at 1/1000 patient-years [11]. It has also been noted that such arrests tend to be refractory to resuscitation [12]. Obtain an ECG and ECHO prior to providing an anesthetic. However, it appears that the severity of SVAS is not a predictor of sudden death [13]. Check for hypercalcemia and manage if present. The anesthetic plan should anticipate a possible difficult airway due to dental abnormalities and mandibular hypoplasia [1].

Other: The WBSCR is near the gene for the L-type voltage gated calcium channel alpha-2/delta subunit 7q11.23-q21.1 that has been implicated in some forms of malignant hyperthermia (MH) susceptibility. There is one case report of a child developing masseter spasm with halothane without progression to MH, and another report of a child developing an elevated temperature and creatinine phosphokinase (CPK) after general anesthetic with sevoflurane, N₂O, and oxygen, that resolved 12 hours after the anesthetic. It is probably best to avoid succinylcholine and be alert to signs of MH if using volatile agents [1].

Further reference: GeneReviews® – www.ncbi.nlm.nih.gov/books/NBK1249.

CHARGE: A syndrome with multiple features due to a mutation in CHD7, at locus 8q12, with autosomal dominant inheritance.

Incidence: 1:13 000–1:15 000 live births [1].

Diagnosis: The definitive diagnosis of CHARGE syndrome requires having all four major features or three major and three minor features (see below).

Clinical features: CHARGE is an acronym for coloboma, heart defects, choanal atresia, retarded growth and development, genital abnormalities, ear anomalies.

Major features: coloboma, choanal atresia or stenosis, cranial nerve dysfunction or anomaly (CN I and VIII particularly frequent), and characteristic ear.
Minor features: genital hypoplasia, developmental delay, cardiovascular malformation (present in 75–85 percent), growth deficiency, orofacial cleft, tracheoesophageal fistula (15–20 percent), distinctive facial features.

Cardiac malformations include atrioventricular canal defects, conotruncal defects (e.g., ToF), aortic arch anomalies, hypoplastic left heart syndrome, and patent ductus arteriosus. Facial features include square face with broad forehead, prominent nasal bridge, flat midface, midface hypoplasia, and micrognathia. Tracheomalacia and subglottic stenosis are occasionally seen.

Anesthetic considerations: Choanal atresia is bilateral in 50 percent of cases and these neonates, as obligate nasal breathers, may present to the operating room for stent placement. Define cardiac anatomy with echocardiography. Anticipate possible difficult mask ventilation and intubation due to micrognathia, midface hypoplasia, and cleft lip and palate. A smaller ETT may be required if subglottic stenosis is present. Patients with CHARGE are at high risk for aspiration due to CN IX and X anomalies ± presence of tracheoesophageal fistulae. The risk of a difficult airway must be weighed against the possibility of aspiration for each patient.

Other: If a difficult airway is expected, only give muscle relaxants once the airway is secured. Check if subacute bacterial endocarditis prophylaxis is indicated.

Further reference: GeneReviews® – www.ncbi.nlm.nih.gov/books/NBK1117 and .

Noonan syndrome: A genetic syndrome characterized by short stature, congenital heart defects, and developmental delay. Several genes are implicated: PTPN11, SOS1, RAF1, and KRAS to name the most common.

Incidence: 1:1000–1:2500 live births. Females and males are equally affected [1].

Diagnosis: The clinical diagnosis is based on the presence of key features. A variety of single gene mutations have been reported in affected individuals, the most common being a mutation in PTPN11 in 50 percent of cases. It has been called “Turner-like syndrome” though the karyotype in Noonan’s syndrome is normal [14].

Clinical features: Short stature, congenital heart defects, and developmental delay are characteristic. Other important features include broad/webbed neck, abnormal chest shape with pectus carinatum and excavatum, low-set nipples, cryptorchidism in males, characteristic facies (most apparent in newborns and children) include low-set posteriorly rotated ears, vivid blue/green irises, wide-set eyes, epicanthal folds, thick eyelids. Coagulation defects may also be present. The most common cardiac anomalies include pulmonary stenosis, hypertrophic cardiomyopathy, atrial septal defect, ToF, atrioventricular canal defects, and coarctation of the aorta [1]. It has been reported that many patients with Noonan syndrome have a history of abnormal bruising or bleeding. A recent case series of patients with PTPN11 mutations, however, suggests that the rates of actual coagulopathy are lower than initially thought [15].

Anesthetic considerations: Carefully evaluate for the potentially difficult airway, cervical spine instability, and cardiac abnormalities. A history of abnormal bleeding should be sought and first-line coagulation studies should be obtained.

Other: There are reports that isoflurane can cause tachycardia. Noonan-like features in infancy are seen in King Denborough syndrome (an MH-susceptible disorder) [1].

Further reference: GeneReviews® – www.ncbi.nlm.nih.gov/books/NBK1124.

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