Paula Goldenberg

Practical guidelines for managing patients with 22q11.2 deletion syndrome

A 12-year-old boy currently is followed by multiple sub-specialists for problems caused by the chromosome 22q11.2 deletion syndrome (22q11DS) (Figure). He was born via spontaneous vaginal delivery, weighing 3033 g, to a 31-year-old G3P3 mother after a full-term pregnancy complicated only by mild polyhydramnios. Family history was non-contributory. Apgar scores were 8 at 1 minute and 9 at 5 minutes. With the exception of a weak cry, the results of the infant’s initial examination were unremarkable, and he was moved to the well-baby nursery. Shortly thereafter, a cardiac murmur was noted, the cardiology department was consulted, and the child was transferred to a local tertiary care facility with a diagnosis of tetralogy of Fallot. Stable, he was discharged home at 3 days of life. Figure Mild dysmorphic facial features of a boy aged 11 years with 22q11.2DS, including a short forehead, hooded eyelids with upslanting palpebral fissures, malar flatness, bulbous nasal tip with hypoplastic alae nasi, and protuberant ears. At 5 days of life, he had jerky movements. On presentation to the local emergency department, his total calcium level was 4.7 mg/dL, and later partial hypoparathyroidism was diagnosed. At that time, a consulting geneticist suggested the diagnosis of chromosome 22q11DS. Weeks later, the family received a telephone call confirming the diagnosis with fluorescence in situ hybridization (FISH). No additional information about the diagnosis, prognosis, etiology, or recurrence risk was provided until the child was 5 months of age, when he underwent cardiac repair at a third hospital, where a comprehensive 22q11DS program was in operation. In the interim, the child had feeding difficulties requiring supplemental nasogastric tube feeds, nasal regurgitation, and gastroesophageal reflux, while the parents searched the internet for reliable information about their son’s diagnosis. Subsequent notable abnormalities and interventions included: recurrent otitis media with bilateral myringotomy tube placement at 6 months; angioplasty with left pulmonary artery stent placement after the identification of pulmonary artery stenosis with bilateral pleural effusions at age 6 years; chronic upper respiratory infections with significant T cell dysfunction requiring live viral vaccines to be held until age 7 years; velopharyngeal incompetence necessitating posterior pharyngeal flap surgery at 7 years; enamel hypoplasia and numerous caries resulting in 3 separate dental procedures under general cardiac anesthesia beginning at age 7 years; multiple cervical and thoracic vertebral anomalies with thoracic levoconvex scoliosis and upper lumbar dextroscoliosis requiring growing rod placement at age 11 years with subsequent rod extension at ages 11.5 and 12 years; postoperative hypocalcemia; short stature; constipation; and persistent idiopathic thrombocytopenia. Pertinent negative test results included normal renal ultrasound scanning and parental 22q11.2 deletion studies. On physical examination, the boy’s height and weight have consistently tracked just below the fifth percentile, with no evidence of growth hormone deficiency. His head circumference is within reference range at the 25th percentile. Dysmorphic features include: a low anterior hairline; hooded eyelids; malar flatness; normally formed but protuberant ears with attached lobes; a mildly deviated nose with a bulbous nasal tip and hypoplastic alae nasi; asymmetric crying facies with a thin upper lip; mild micrognathia; a sacral dimple; and soft tissue syndactyly of the second and third toes. Developmentally, the boy had mild delays in achieving motor milestones, sitting at 11 months and walking at 18 months. However, he exhibited significant delays in the emergence of language: he never babbled, spoke his first words at age 3 years, and only achieved full conversational speech at 7 years. However, he had relative strengths in receptive language and communicated appropriately by the use of sign language. Now quite conversant, he is mainstreamed in the seventh grade with resource room supports. Moreover, he is affable, but exhibits anxiety and perseverations. Lastly, despite numerous medical, academic, and social challenges, he participates in assisted athletics, is an avid wrestling fan, and enjoys travel. However, his exceptionally supportive parents, siblings, and extended family continue to worry about his long-term outcome and transition of care as he approaches adulthood. As demonstrated by this boy’s complicated course, practical multi-system guidelines are needed to assist the general practitioner and specialists in caring for patients with 22q11DS. Although still under-recognized, detection, including in the prenatal setting, is increasing. Moreover, the phenotypic spectrum is highly variable, and patients may present at any age. Thus, initial guidelines developed by an international panel of experts present the best practice recommendations currently available across the lifespan, with a major focus on the changing issues through childhood development.

Cross-reactive immunologic material status affects treatment outcomes in Pompe disease infants

Deficiency of acid alpha glucosidase (GAA) causes Pompe disease, which is usually fatal if onset occurs in infancy. Patients synthesize a non-functional form of GAA or are unable to form native enzyme. Enzyme replacement therapy with recombinant human GAA (rhGAA) prolongs survival in infantile Pompe patients but may be less effective in cross-reactive immunologic material (CRIM)-negative patients. We retrospectively analyzed the influence of CRIM status on outcome in 21 CRIM-positive and 11 CRIM-negative infantile Pompe patients receiving rhGAA. Patients were from the clinical setting and from clinical trials of rhGAA, were 6 months of age, were not invasively ventilated, and were treated with IV rhGAA at a cumulative or total dose of 20 or 40 mg/kg/2 weeks. Outcome measures included survival, invasive ventilator-free survival, cardiac status, gross motor development, development of antibodies to rhGAA, and levels of urinary Glc(4). Following 52 weeks of treatment, 6/11 (54.5%) CRIM-negative and 1/21 (4.8%) CRIM-positive patients were deceased or invasively ventilated (p<0.0001). By age 27.1 months, all CRIM-negative patients and 4/21 (19.0%) CRIM-positive patients were deceased or invasively ventilated. Cardiac function and gross motor development improved significantly more in the CRIM-positive group. IgG antibodies to rhGAA developed earlier and serotiters were higher and more sustained in the CRIM-negative group. CRIM-negative status predicted reduced overall survival and invasive ventilator-free survival and poorer clinical outcomes in infants with Pompe disease treated with rhGAA. The effect of CRIM status on outcome appears to be mediated by antibody responses to the exogenous protein.

Remarkable improvement in adult Leigh syndrome with partial cytochrome c oxidase deficiency

Leigh syndrome (LS) is a heterogeneous disorder, usually due to a defect in oxidative metabolism. Typically, signs and symptoms commence in infancy or childhood, although rare cases of adult onset have been described. Progressive deterioration is the norm. The authors describe a 22-year-old woman with partial cytochrome c oxidase deficiency who developed fulminant LS following an acute febrile illness and who subsequently showed dramatic clinical and neuroradiologic improvement.

Expanding the Phenotype Associated with NAA10-Related N-Terminal Acetylation Deficiency

N‐terminal acetylation is a common protein modification in eukaryotes associated with numerous cellular processes. Inherited mutations in NAA10, encoding the catalytic subunit of the major N‐terminal acetylation complex NatA have been associated with diverse, syndromic X‐linked recessive disorders, whereas de novo missense mutations have been reported in one male and one female individual with severe intellectual disability but otherwise unspecific phenotypes. Thus, the full genetic and clinical spectrum of NAA10 deficiency is yet to be delineated. We identified three different novel and one known missense mutation in NAA10, de novo in 11 females, and due to maternal germ line mosaicism in another girl and her more severely affected and deceased brother. In vitro enzymatic assays for the novel, recurrent mutations p.(Arg83Cys) and p.(Phe128Leu) revealed reduced catalytic activity. X‐inactivation was random in five females. The core phenotype of X‐linked NAA10‐related N‐terminal‐acetyltransferase deficiency in both males and females includes developmental delay, severe intellectual disability, postnatal growth failure with severe microcephaly, and skeletal or cardiac anomalies. Genotype–phenotype correlations within and between both genders are complex and may include various factors such as location and nature of mutations, enzymatic stability and activity, and X‐inactivation in females.

Computerized neurocognitive profile in young people with 22q11.2 deletion syndrome compared to youths with schizophrenia and At‐Risk for psychosis

Adults with 22q11.2 Deletion syndrome (22q11DS) have increased prevalence of schizophrenia features. Our goal is to compare the neurocognitive profile in 22q11DS, schizophrenia and individuals at risk for schizophrenia. Twenty‐one 22q11DS patients (8–32 years, mean 14.9 years, 15M, 6F) were matched to four comparison groups on age: low risk (n = 21), first‐degree family members of schizophrenia patients (genetic risk, n = 20), individuals exhibiting putatively prodromal symptoms (clinical risk, n = 19), and patients with schizophrenia (n = 21). All participants received semi‐structured interviews [Diagnostic Interview for Genetic Studies (DIGS) and the Structured Interview for Prodromal Syndromes (SIPS)], and a computerized neurocognitive battery (CNB) measuring the following domains: Abstraction and Mental Flexibility, Attention, Working Memory, Verbal Memory, Face Memory, Spatial Memory, Language, Spatial Processing, Sensorimotor Dexterity, and Emotion Processing. Sixty percent of 22q11DS participants met SIPS criteria for prodromal symptoms and one participant met criteria for paranoid schizophrenia. Thirty‐eight percent met criteria for Depressive Disorders. All 22q11DS participants successfully completed the CNB. 22q11DS participants were significantly less accurate in nearly all domains, but had similar speed of response compared to the other groups. Their profile resembled that of the psychosis groups in accuracy and speed, except for more pronounced deficits in accuracy for face memory and emotion processing. Subthreshold psychotic symptoms are present in a high proportion of 22q11DS participants. Deficits shown in the CNB are more pronounced for accuracy than speed relative to the psychosis groups with similar profiles. Similar deficits have been described in the 22q11DS population using non‐computerized measures, which require increased testing time.

Aortopathy in the 7q11.23 microduplication syndrome

The 7q11.23 microduplication syndrome, caused by the reciprocal duplication of the Williams‐Beuren syndrome deletion region, is a genomic disorder with an emerging clinical phenotype. Dysmorphic features, congenital anomalies, hypotonia, developmental delay highlighted by variable speech delay, and autistic features are characteristic findings. Congenital heart defects, most commonly patent ductus arteriosus, have been reported in a minority of cases. Included in the duplicated region is elastin (ELN), implicated as the cause of supravalvar aortic stenosis in patients with Williams–Beuren syndrome. Here we present a series of eight pediatric patients and one adult with 7q11.23 microduplication syndrome, all of whom had aortic dilation, the opposite vascular phenotype of the typical supravalvar aortic stenosis found in Williams–Beuren syndrome. The ascending aorta was most commonly involved, while dilation was less frequently identified at the aortic root and sinotubular junction. The findings in these patients support a recommendation for cardiovascular surveillance in patients with 7q11.23 microduplication syndrome.

Clinical experience with array CGH: Case presentations from nine months of practice

A total of 124 individuals were tested in the initial 9 months that array CGH technology was offered to clinical genetics patients. In 11 of these patients array CGH identified a previously unsuspected diagnosis. A suspected diagnosis was confirmed in three patients. A single case in this series proved to be a polymorphic copy number variant. This paper describes five of the patients with previously unsuspected diagnoses in detail. We suggest that array CGH is an improved tool ready for routine use in clinical genetics.

Evidence-based medicine and practice guidelines: Application to genetics

The Professional Practice and Guidelines Committee of the American College of Medical Genetics has the responsibility of overseeing the development of guidelines for the practice of clinical genetics. In the past, most, if not all, guidelines were primarily based on expert opinion. However, recently the goal has become to develop guidelines that are more evidence‐based, or at least, to recognize the level of evidence available to the authors of these documents. This article reviews the challenges that are faced by geneticists who are charged with the development of practice guidelines.

Dilated cardiomyopathy in a 32-year-old woman with Russell-Silver syndrome.

INTRODUCTION Russell-Silver Syndrome (RSS) is a genetically determined condition characterized by severe intrauterine and postnatal growth retardation; relative macrocephaly; a small, triangular face; and fifth-finger clinodactyly. The etiology of RSS involves epigenetic regulation through either uniparental disomy or genomic imprinting via DNA methylation. There has been no documented association between RSS and cardiomyopathy. METHODS We present an original case of a 32-year-old woman with RSS with dilated a cardiomyopathy who on cardiac biopsy showed occasional hypertrophic and atrophic myocytes with no evidence of inflammation, abnormal sarcomeres and disintegration of the Z bands on ultrastructural analysis, abnormal desmin, and normal C9 immunoreactivity. CONCLUSION This case represents the first reported association between RSS and cardiomyopathy. Given the complex mechanisms of disease etiology in RSS, this novel case provides insights into the mechanism of progressive dilated cardiomyopathy in an older individual with RSS.

High burden of genetic conditions diagnosed in a cardiac neurodevelopmental clinic.

BACKGROUND There is a known high prevalence of genetic and clinical syndrome diagnoses in the paediatric cardiac population. These disorders often have multisystem effects, which may have an important impact on neurodevelopmental outcomes. Taken together, these facts suggest that patients and families may benefit from consultation by genetic specialists in a cardiac neurodevelopmental clinic. OBJECTIVE This study assessed the burden of genetic disorders and utility of genetics evaluation in a cardiac neurodevelopmental clinic. METHODS A retrospective chart review was conducted of patients evaluated in a cardiac neurodevelopmental clinic from 6 December, 2011 to 16 April, 2013. All patients were seen by a cardiovascular geneticist with genetic counselling support. RESULTS A total of 214 patients were included in this study; 64 of these patients had a pre-existing genetic or syndromic diagnosis. Following genetics evaluation, an additional 19 were given a new clinical or laboratory-confirmed genetic diagnosis including environmental such as teratogenic exposures, malformation associations, chromosomal disorders, and single-gene disorders. Genetic testing was recommended for 112 patients; radiological imaging to screen for congenital anomalies for 17 patients; subspecialist medical referrals for 73 patients; and non-genetic clinical laboratory testing for 14 patients. Syndrome-specific guidelines were available and followed for 25 patients with known diagnosis. American Academy of Pediatrics Red Book asplenia guideline recommendations were given for five heterotaxy patients, and family-based cardiac screening was recommended for 23 families affected by left ventricular outflow tract obstruction. CONCLUSION Genetics involvement in a cardiac neurodevelopmental clinic is helpful in identifying new unifying diagnoses and providing syndrome-specific care, which may impact the patients overall health status and neurodevelopmental outcome.