10/26/2016. CMV and Connexin 26 Frontiers of Research and Therapy for Congenital Hearing Loss. CMV and Cx26 Hearing Loss. CMV and Cx26 Hearing Loss

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1 CMV and Connexin 26 Frontiers of Research and Therapy for Congenital Hearing Loss Dylan K. Chan, MD, PhD, FAAP Assistant Professor Pediatric Otolaryngology-Head and Neck Surgery Director, Children s Communication Center University of California, San Francisco dylan.chan@ucsf.edu UCSF Audiology Update XII November 4, 2016 CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research 1

2 Childhood hearing loss Definition Permanent Childhood Hearing Impairment (PCHI) Childhood hearing loss Definition Permanent Childhood Hearing Impairment (PCHI) Mild to profound Bilateral or unilateral All frequencies or some frequencies Stable or progressive Sensorineural or conductive All are eligible by law for services to prevent developmental delay Childhood hearing loss Prevalence How common is PCHI? 2

3 Childhood hearing loss Prevalence Prevalence depends on your exact definition: From newborn/school/pediatrician screening 1:500 newborns (> 40 db HL) 1:300 by age 9 (> 40 db HL) From NHANES survey 1:100 by age 19 (> 25 db HL, bilateral) 1:5 by age 19 (> 15 db HL, any kind, laterality, or frequency) Shargorodsky, 2010 Mild/unilateral hearing loss Impact Children with mild or unilateral hearing loss have impaired school performance, behavior, and psychosocial well-being Mild/moderate hearing loss Bess students, 5.5% with mild SNHL Worse on general education, educational risk, behavior, physical/emotional/social function Unilateral hearing loss Lieu 2010/ children, case-control study Children with UHL had significantly worse speech and language with persistent delays in academic and behavioral performance after 6 years Childhood hearing loss Economic impact Economic cost to the public for an untreated child with hearing loss: $652 million: total cost in the US for education for DHH children ($11,006/ child) $115,600: lifetime direct educational costs for 1 DHH child $420,000: additional direct educational costs (if untreated) $1,000,000: total lifetime (educational costs + lost productivity) $2.1 billion: economic cost to the public for a one-year cohort of DHH children $10 billion: cost if untreated Estimated lifetime costs for all 380,000 children born in one year with asthma $7 billion Johnson, 1993 Corso,

4 Early Intervention Timing matters Yoshinaga-Itano, 1998 Newborn Hearing Screening Goal Diagnosis, medical treatment, and early intervention initiated by 6 months REFER Confirmed hearing loss Birth AABR or DPOAE- based screen By 1 month Outpatient screen/rescreen By 3 months Diagnostic audiology evaluation (ABR) By 6 months Early intervention services initiated Otolaryngology evaluation Ongoing audiology management REFER CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research 4

5 Congenital SNHL Diagnostic workup All children with congenital SNHL 50% acquired 50% genetic CMV 33% syndromic 67% non-syndromic TORCH infections Pendred s Usher s 50% Non-GJB2 50% GJB2 Congenital SNHL Why test? Knowledge Why can t my child hear? Prognosis Is the hearing going to get worse? Exclusion of other causes What else is wrong with my child? Family counseling What does this mean for my other kids? Intervention What can we do about it? hearing.siemens.com Congenital SNHL Diagnostic workup History Physical Exam Diagnostic Tests 5

6 History Syndromic hearing loss Associations with syndromic SNHL apparent from personal or family history Visual impairment Branchial cleft anomalies Thyroid dysfunction/goiter Sudden death/arrhythmia Renal/urinary complaints Pigmentation disorders Usher s Branchio-oto-renal Pendred s Jervell Lange-Nielsen Alport s, branchio-oto-renal Waardenburg Unsure?? Refer to genetics Physical Exam Syndromic hearing loss Associations with syndromic SNHL apparent from physical exam Goiter Pendred s adhb.govt.nz Branchial cleft anomalies/preauricular pits Branchio-oto-renal rg Craniofacial abnormalities Multiple Pigmentation abnormalities Waardenburg s History Non-syndromic hearing loss Causes of non-syndromic SNHL apparent from history Infectious Toxoplasmosis, syphilis, rubella, CMV, HSV, meningitis Ototoxic drugs Gentamicin, cisplatin Genetic Family history, consanguinity Hyperbilirubinemia Jaundice Trauma EVA-related sudden hearing loss 6

7 Idiopathic Non-syndromic SNHL Core diagnostic tests 1) Imaging 1) CT 2) MRI 2) Genetic testing 1) Connexin 26/30 2) Complete hearing loss gene array testing 3) CMV testing 1) Urine PCR (active infection) 2) Newborn blood spot PCR (congenital infection) Idiopathic Non-syndromic SNHL Core diagnostic tests 1) Imaging 1) CT 2) MRI 2) Genetic testing 1) Connexin 26/30 2) Complete hearing loss gene array testing 3) CMV testing 1) Urine PCR (active infection) 2) Newborn blood spot PCR (congenital infection) Imaging Impact How does information gleaned from imaging affect patient management? Cochlear nerve hypoplasia cochlear implant candidacy Temporal-bone abnormalities surgical planning Yan et al., 2013 EVA recommendations regarding head trauma 7

8 EVA Head trauma Alemi, Meta-analysis of EVA, head trauma, and progressive hearing loss - EVA is associated with 40% risk of long-term progressive SNHL - There is no association between head trauma and risk for long-term progression of hearing loss in people with EVA - I do NOT recommend special precautions for head trauma relating to EVA Imaging Recommendations 1) Cochlear implant candidates MRI with or without CT 2) All others MRI or CT after discussion with parents (age, cost, anxiety) 3) No special precautions for head trauma relating to EVA Idiopathic Non-syndromic SNHL Core diagnostic tests 1) Imaging 1) CT 2) MRI 2) Genetic testing 1) Connexin 26/30 2) Complete hearing loss gene array testing 3) CMV testing 1) Urine PCR (active infection) 2) Newborn blood spot PCR (congenital infection) 8

9 Genetic Testing Impact Any cause identified genetic counseling/family planning Syndromic association identified careful screening for associated phenotype Specific mutations increased risk of progressive hearing loss, ototoxicity Future therapeutic options gene therapy Genetic testing Available tests Test Location #genes tested Turnaround time Cost/insurance Indication GJB2/GJB6 (Connexin 26/30) Pendred s/ SLC26A4 Usher s panel Multiple (Quest) Stanford, Cincinnati, Boston Cincinnati, Boston wks $300 / yes Nonsyndromic SNHL wks $1100 / yes SNHL + EVA or thyroid dysfunction wks $2500 / yes SNHL + visual dysfunction OtoScope Iowa months $1500 / no Any congenital hearing loss Exome sequencing Referral to genetics All Varies Varies / no Any congenital hearing loss Genetic testing Available tests Test Location #genes tested Turnaround time Cost/insurance Indication GJB2/GJB6 (Connexin 26/30) Pendred s/ SLC26A4 Usher s panel Multiple (Quest) Stanford, Cincinnati, Boston Cincinnati, Boston wks $300 / yes Nonsyndromic SNHL wks $1100 / yes SNHL + EVA or thyroid dysfunction wks $2500 / yes SNHL + visual dysfunction OtoScope Iowa months $1500 / no Any congenital hearing loss Exome sequencing Referral to genetics All Varies Varies / no Any congenital hearing loss 9

10 Genetic testing Available tests Test Location #genes tested Turnaround time Cost/insurance Indication GJB2/GJB6 (Connexin 26/30) Pendred s/ SLC26A4 Usher s panel Multiple (Quest) Stanford, Cincinnati, Boston Cincinnati, Boston wks $300 / yes Nonsyndromic SNHL wks $1100 / yes SNHL + EVA or thyroid dysfunction wks $2500 / yes SNHL + visual dysfunction OtoScope Iowa months $1500 / no Any congenital hearing loss Exome sequencing Referral to genetics All Varies Varies / no Any congenital hearing loss Genetic testing Available tests Test Location #genes tested Turnaround time Cost/insurance Indication GJB2/GJB6 (Connexin 26/30) Pendred s/ SLC26A4 Usher s panel Multiple (Quest) Stanford, Cincinnati, Boston Cincinnati, Boston wks $300 / yes Nonsyndromic SNHL wks $1100 / yes SNHL + EVA or thyroid dysfunction wks $2500 / yes SNHL + visual dysfunction OtoScope Iowa months $1500 / no Any congenital hearing loss Exome sequencing Referral to genetics All Varies Varies / no Any congenital hearing loss Genetic testing Available tests Test Location #genes tested Turnaround time Cost/insurance Indication GJB2/GJB6 (Connexin 26/30) Pendred s/ SLC26A4 Usher s panel Multiple (Quest) Stanford, Cincinnati, Boston Cincinnati, Boston wks $300 / yes Nonsyndromic SNHL wks $1100 / yes SNHL + EVA or thyroid dysfunction wks $2500 / yes SNHL + visual dysfunction OtoScope Iowa months $1500 / no Any congenital hearing loss Exome sequencing Referral to genetics All Varies Varies / no Any congenital hearing loss 10

11 Idiopathic Non-syndromic SNHL Core diagnostic tests 1) Imaging 1) CT 2) MRI 2) Genetic testing 1) Connexin 26/30 2) Complete hearing loss gene array testing 3) CMV testing 1) Urine PCR (active infection) 2) Newborn blood spot PCR (congenital infection) CMV Congenital Hearing Loss 15-20% of all congenital hearing loss More common in lower socioeconomic strata Often progressive May be syndromic Can be treated Core diagnostic tests How to choose? Neonates < 2 weeks old CMV testing ASAP Cochlear implant candidate MRI -> Cx26/CMV* Unilateral CMV* -> imaging at appropriate age -> Cx26 All others Cx26/CMV* -> imaging at appropriate age * CMV testing only by dried blood spot if > 2 weeks. If unable, skip ** If no findings from core testing, consider full genetic array testing Order and type of testing depends on many patient factors, systems consideration, and family preference 11

12 CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research 12

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14 CMV-associated SNHL noted to progress and/or newly develop up to teenage years 20-30% of CMV(+) will have SNHL /1000 live births = 1000 new cases/year in the US May be vastly underestimated Take home point 1 CMV-associated hearing loss Highly variable Frequently progressive Onset/progression throughout childhood Occurs with or without other symptoms ONLY occurs with prenatal transmission 14

15 CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research CMV Testing Prenatal screening healthy pregnant women - not routinely done Newborn screening saliva PCR assays - not routinely done Neonatal (up to 2-3 weeks) culture or PCR from urine or blood - gold standard Postnatal PCR assay from dried newborn blood spots - 99% specificity - 30% sensitivity SNHL CMV DBS testing DBS CMV PCR (vs saliva culture) 34.4% sensitivity 99.9% specificity Boppana et al., JAMA

16 Take home point 2 CMV testing CMV testing (CMV PCR/culture) is sensitive and specific before 3 weeks Is sensitive but NOT specific after 3 weeks CMV DBS testing Is specific but NOT sensitive Is the only specific test after 3 weeks Question: What is the best testing/screening paradigm to efficiently and accurately identify congenital CMVassociated hearing loss? 1) Universal neonatal CMV screening 2) Hearing-targeted CMV screening NHS and CMV screening CHIMES data Ross (UAB) AAP NCE 2014 CMV and newborn hearing screening (NHS) in 100,000 newborns CMV - CMV + NHS PASS 97, Hearing unknown NHS REFER SNHL 12 No SNHL 16

17 NHS and CMV screening CHIMES data + All asymptomatic neonates 100,000 2% refer NHS % pass NHS 98, % CMV % + CMV % CMV 97, % + CMV % SNHL (295) 63% SNHL % SNHL ( ) 7 15% SNHL (30 60) NHS and CMV screening CHIMES data + All asymptomatic neonates 100,000 2% refer NHS % pass NHS 98, % CMV % + CMV % CMV 97, % + CMV % SNHL (295) 63% SNHL % SNHL ( ) 7 15% SNHL (30 60) NNT = 100 to identify one case of congenital CMV associated SNHL for treatment NHS and CMV screening Criticism All asymptomatic neonates 100,000 2% refer NHS % pass NHS 98, % CMV % + CMV % CMV 97, % + CMV % SNHL (295) 63% SNHL % SNHL ( ) 7 15% SNHL (30 60) This method will miss CMV +children who pass NHS and later develop progressive SNHL 17

18 NHS and CMV screening Criticism All asymptomatic neonates 100,000 2% refer NHS % pass NHS 98, % CMV % + CMV % CMV 97, % + CMV % SNHL (295) 63% SNHL % SNHL ( ) 7 15% SNHL (30 60) Is this method an effective means for identifying babies at risk for congenital CMV? Yield of CMV + is 1.6% vs 0.4%. But still misses 93% of CMV + babies. Take home point 3 identification of CMVassociated hearing loss Universal CMV screening would be ideal Hearing-targeted CMV screening misses many potential cases, but is the best current option CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research 18

19 Treatment Valganciclovir for CMV hearing loss NIAID Collaborative Antiviral Study Group Kimberlin et al., NEJM 372(10): Multinational 31-institution Phase III randomized, controlled clinical trial 109 infants < 30 days old Symptomatic congenital CMV 43% with baseline hearing loss 6 wks vs. 6 mos PO valganciclovir 24-month follow up Significantly increased odds of hearing improvement or stabilization of normal hearing with 6-month course (OR ( ) at 24 months) V-GCV for congenital CMV Utah study HT-CMV screening-directed treatment for congenital CMV-associated hearing loss Study sites 25 sites; coordinator Albert Park (OHNS, University of Utah); Inclusion Referred NHS and subsequent CMV + by urine/saliva PCR or culture Goal Determine hearing, speech, language, developmental outcomes of infants with referred NHS entered into a pathway of early CMV screening and subsequent treatment (placebo vs. valganciclovir) 19

20 CMV-associated SNHL New Kimberlin study NCT (Valgan Toddler Study) Multi-institution Phase II randomized, controlled clinical trial 6 wks PO valganciclovir vs. placebo Age 1 month 4 years with sensorineural hearing loss Congenital CMV by neonatal urine CMV or dried blood spot CMV Take home point 4 CMV treatment (6 months valganciclovir) Can prevent progression of hearing loss Is of unknown efficacy in kids with isolated CMV-associated hearing loss AND in older kids CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research 20

21 CMV-associated SNHL Practice guidelines Babies under 3 weeks of age with referred NHS - CMV testing (urine/saliva PCR or culture) - Diagnostic audiologic testing Babies over 3 weeks of age with referred NHS - Diagnostic audiologic testing Babies and children over 3 weeks of age up to 4 years of age with confirmed SNHL - CMV DBS testing (as part of diagnostic workup for SNHL) - Consider V-GCV if positive Children over 4 years of age with confirmed SNHL - CMV DBS testing (purely for diagnostic workup for SNHL) Hearing-targeted CMV screening 1) Babies under 3 weeks of age with referred NHS - CMV testing (urine/saliva PCR or culture) - Diagnostic audiologic testing 2) Babies over 3 weeks of age with referred NHS - Diagnostic audiologic testing State law in UT, CT, MN, IL 3) Babies and children over 3 weeks of age with confirmed SNHL - CMV DBS testing (as part of diagnostic workup for SNHL) - Consider V-GCV if positive CMV-associated hearing loss Take-home If you see a baby < 3 weeks old for a referred newborn hearing screen, recommend discussion with pediatrician/ohns about CMV testing If you are involved with your hospital s NHS program, consider hearing-targeted CMV testing 21

22 CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research Cx26 hearing loss Prevalence among all hearing impaired 0-10% 10-20% 20-30% 30-40% >40% 54 countries 141 studies hearing-loss probands 4064 GJB2 biallelic probands Frequency = 18% Chan and Chang, 2015 Cx26 hearing loss Severity 100% Percent of individuals 50% profound severe moderate mild 0% T/T NT/T NT/NT Genotype 1531 probands Snoeckx et al.,

23 Cx26 hearing loss Progression and V37I Frequency (khz) Pure tone threshold (db) Initial audiogram Final audiogram Thresholds averaged from 7 V37I/V37I individuals with progressive hearing loss CMV and Cx26 Hearing Loss Background Congenital hearing loss Prevalence and impact CMV-associated SNHL Overview Treatment Current management Cx26-associated SNHL Clinical overview Research Cx26 GJB2 gene GJB2 (gap junction protein, beta 2) Chromosome location13q11-q12 protein Connexin 26 Expressed in cochlea and epidermis Forms heteromeric/heterotypic gap-junction channels and apical hemichannels with Connexin 30 Ions, small molecules, electrical currents, cell adhesion 23

24 Connexin function K+ recycling K + K + K + K+ Connexin independent Connexin dependent Connexin function Noise detection Noise ATP Connexin independent Connexin dependent Ca 2+ waves MAPK Cx26 dysfunction Animal models Mouse (genetic model) Gerbil (physiologic model) 24

25 Cx26 dysfunction Animal models Mouse (genetic model) Gerbil (physiologic model) Mouse Inducible Cx26 KO ER-Cre/Cx26-lox TMX Cre Cx26 ER loxp loxp TMX-inducible Cx26 cko Progressive hearing loss Zhu,

26 TMX-inducible Cx26 cko Noise-induced hearing loss 103 db, 2 hr octave-band noise 80 Click ABR threshold (db SPL) Wild-type WT Connexin-26 Cx26 knockout Baseline Days Permanent shift Cx26 dysfunction Animal models Connexin 26 deficient mice have increased susceptibility to age and noise induced hearing loss Cx26 dysfunction Animal models Connexin 26 deficient mice have increased susceptibility to age and noise induced hearing loss Connexin 26 may protect against cochlear trauma 26

27 Cx26 dysfunction Animal models Connexin 26 deficient mice have increased susceptibility to age and noise induced hearing loss Connexin 26 may protect against cochlear trauma How? Cx26 dysfunction Animal models Mouse (genetic model) Gerbil (physiologic model) Adult gerbil cochlear physiology in vitro Acoustic stimulus Endolymph Calcium imaging Cochlear stroboscopy Endocochlear potential Microphonic potential Perilymph 27

28 In vitro Cochlear explant Medial Ventral Dorsal 50 µm Lateral Chan and Hudspeth, 2005 In vitro Cochlear explant Medial 10 µm Lateral Chan and Hudspeth, 2005 Noise-exposure Cochlear stroboscopy 1000 Hz, 100 db SPL Chan and Hudspeth,

29 Noise exposure Intercellular Ca 2+ signalling A B C D A OHCs 50 M Adult gerbil cochlear explant E 0.9 F slope = 6.2 m/s Ratio (340/387) s Distance (mm) Time (s) Cx26 dysfunction Animal models Connexin 26 protects against cochlear trauma Calcium signalling in cochlear supporting cells is involved Cx26 dysfunction From rodents to humans Connexin 26 protects against cochlear trauma Are people with Connexin 26 mutations more susceptible to NIHL? Calcium signalling in cochlear supporting cells is involved Could calcium regulation in the cochlea be a potential drug target? What about gene therapy? 29

30 Connexin 26 Gene therapy What about gene therapy? Connexin 26 Gene therapy Normal cochlea Long-deafened cochlea Connexin 26 Gene therapy The risks and benefits of intervention now are unclear with respect to future therapies We need to support your child s hearing and communication development now 30

31 Cx26 hearing loss Summary Connexin 26 is the most common gene affected in congenital SNHL and has highly variable presentation Connexin 26-associated hearing loss may be due to changes in calcium regulation in the cochlea that make it break down more easily This may lead to new drug targets or gene therapy in the future Let s take care of our kids now Thanks 31

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33 Cochlear implantation Cost effectiveness Unilateral Cochlear Implant Estimated cost per QALY: $9,000 Once accounting for indirect costs (including reduced educational expenses): Savings of $53,000 per child Cheng, 2000 Lammers,

34 Early Intervention Timing matters Receptive language Expressive language Cochlear implantation at < 18 months months >36 months Niparko, JAMA 2010 How was hearing loss detected? Age Degree Newborn Infant Preschooler Schoolchild Profound Moderate Mild/unilateral Sign Unresponsive to sound Speech/ language Education/ behavior How was hearing loss detected? Age Degree Newborn Infant Preschooler Schoolchild Profound Moderate Mild/unilateral Sign Unresponsive to sound Speech/ language Education/ behavior 34

35 Diagnostic tests Congenital hearing loss What next? 1) Work up potential causes revealed in H&P Visual loss -> ophthalmology consult Urinary problems -> renal US Branchial cleft anomalies -> renal US Goiter or thyroid problems -> TFTs, genetic testing (SLC26A4), imaging (EVA) History of syncope or arrhythmia -> EKG ANY syndromic association -> genetics consult Unsure?? Refer to genetics Diagnostic tests Congenital hearing loss What next? 1) Work up potential causes revealed in H&P Visual loss -> ophthalmology consult Urinary problems -> renal US Branchial cleft anomalies -> renal US Goiter or thyroid problems -> TFTs, genetic testing (SLC26A4), imaging (EVA) History of syncope or arrhythmia -> EKG ANY syndromic association -> genetics consult 2) If H&P/genetics evaluation unrevealing: do NOT empirically pursue these tests for specific syndromic causes. DO consider one of three core diagnostic tests Imaging CT vs MRI Right: MRI Better neural anatomy No radiation More sedation More expensive More incidental findings CT Better bony anatomy + radiation Less sedation Less expensive Less incidental findings 35

36 Genetic testing Recommendations 1) GJB2/Connexin 26 testing 2) Refer to genetics for consideration of other testing 36