@article {855, title = {Genome-Wide Polygenic Score, Clinical Risk Factors, and Long-Term Trajectories of Coronary Artery Disease.}, journal = {Arterioscler Thromb Vasc Biol}, volume = {40}, year = {2020}, month = {2020 11}, pages = {2738-2746}, abstract = {

OBJECTIVE: To determine the relationship of a genome-wide polygenic score for coronary artery disease (GPS) with lifetime trajectories of CAD risk, directly compare its predictive capacity to traditional risk factors, and assess its interplay with the Pooled Cohort Equations (PCE) clinical risk estimator. Approach and Results: We studied GPS in 28 556 middle-aged participants of the Malm{\"o} Diet and Cancer Study, of whom 4122 (14.4\%) developed CAD over a median follow-up of 21.3 years. A pronounced gradient in lifetime risk of CAD was observed-16\% for those in the lowest GPS decile to 48\% in the highest. We evaluated the discriminative capacity of the GPS-as assessed by change in the C-statistic from a baseline model including age and sex-among 5685 individuals with PCE risk estimates available. The increment for the GPS (+0.045, <0.001) was higher than for any of 11 traditional risk factors (range +0.007 to +0.032). Minimal correlation was observed between GPS and 10-year risk defined by the PCE (=0.03), and addition of GPS improved the C-statistic of the PCE model by 0.026. A significant gradient in lifetime risk was observed for the GPS, even among individuals within a given PCE clinical risk stratum. We replicated key findings-noting strikingly consistent results-in 325 003 participants of the UK Biobank.

CONCLUSIONS: GPS-a risk estimator available from birth-stratifies individuals into varying trajectories of clinical risk for CAD. Implementation of GPS may enable identification of high-risk individuals early in life, decades in advance of manifest risk factors or disease.

}, keywords = {Adult, Aged, Coronary Artery Disease, Female, Genetic Predisposition to Disease, Genome-Wide Association Study, Heart Disease Risk Factors, Heredity, Humans, Incidence, Male, Middle Aged, Multifactorial Inheritance, Phenotype, Prognosis, Risk Assessment, Sweden, Time Factors, United Kingdom}, issn = {1524-4636}, doi = {10.1161/ATVBAHA.120.314856}, author = {Hindy, George and Aragam, Krishna G and Ng, Kenney and Chaffin, Mark and Lotta, Luca A and Baras, Aris and Drake, Isabel and Orho-Melander, Marju and Melander, Olle and Kathiresan, Sekar and Khera, Amit V} } @article {938, title = {Natural history of Ollier disease and Maffucci syndrome: Patient survey and review of clinical literature.}, journal = {Am J Med Genet A}, volume = {182}, year = {2020}, month = {2020 05}, pages = {1093-1103}, abstract = {

Ollier disease (OD) and Maffucci syndrome (MS) are characterized by multiple enchondromas. Patients with MS also have benign vascular overgrowths that become malignant in 8.5\% of cases. OD is characterized by multiple enchondromas, typically unilateral in distribution with a predilection for the appendicular skeleton. MS is characterized by multiple enchondromas bilaterally distributed in most of the cases. Both disorders feature multiple swellings on the extremity, deformity around the joints, limitations in joint mobility, scoliosis, bone shortening, leg-length discrepancy, gait disturbances, pain, loss of function, and pathological fractures. About 50\% of patients with OD or MS develop a malignancy, such as chondrosarcoma, glioma, and ovarian juvenile granulosa cell tumor. To better understand the natural history of OD and MS, we reviewed 287 papers describing patients with OD and MS. We also created a survey that was distributed directly to 162 patients through Facebook. Here, we compare the review of the cases described in the literature to the survey{\textquoteright}s responses. The review of the literature showed that: the patients with OD are diagnosed at a younger age; the prevalence of chondrosarcomas among patients with OD or MS was ~30\%; in four patients, vascular anomalies were identified in internal organs only; and, the prevalence of cancer among patients with OD or MS was ~50\%. With these data, health care providers will better understand the natural history, severity, and prognosis of these diseases and the prevalence of malignancies in these patients. Here, we recommend new guidelines for the care of patients with OD and MS.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Chondrosarcoma, Enchondromatosis, Female, Granulosa Cell Tumor, Humans, Infant, Infant, Newborn, Male, Middle Aged, Ovarian Neoplasms, Prognosis, Young Adult}, issn = {1552-4833}, doi = {10.1002/ajmg.a.61530}, author = {El Abiad, Jad M and Robbins, Sarah M and Cohen, Bernard and Levin, Adam S and Valle, David L and Morris, Carol D and de Macena Sobreira, Nara L} } @article {660, title = {Identification of CACNA1D variants associated with sinoatrial node dysfunction and deafness in additional Pakistani families reveals a clinical significance.}, journal = {J Hum Genet}, volume = {64}, year = {2019}, month = {2019 Feb}, pages = {153-160}, abstract = {

Sinoatrial node dysfunction and deafness (SANDD) syndrome is rare and characterized by a low heart beat and severe-to-profound deafness. Additional features include fatigue, dizziness, and episodic syncope. The sinoatrial node (SAN) drives heart automaticity and continuously regulates heart rate. The CACNA1D gene encoding the Ca1.3 protein expressed in inner hair cells, atria and SAN, induces loss-of-function in channel activity and underlies SANDD. To date, only one variant c.1208_1209insGGG:p.(G403_V404insG) has been reported for SANDD syndrome. We studied five Pakistani families with SANDD and characterized a new missense variant p.(A376V) in CACNA1D in one family, and further characterized the founder variant p.(G403_V404insG) in four additional pedigrees. We show that affected individuals in the four families which segregate p.(G403_V404insG) share a 1.03 MB haplotype on 3p21.1 suggesting they share a common distant ancestor. In conclusion, we identified new and known variants in CACNA1D in five Pakistani families with SANDD. This study is of clinical importance as the CACNA1D founder variant is only observed in families from the Khyber Pakhtunkhwa (KPK) province, in Pakistan. Therefore, screening patients with congenital deafness for SAN dysfunction in this province could ensure adequate follow-up and prevent cardiac failure associated with SAN.

}, keywords = {Adolescent, Calcium Channels, L-Type, Deafness, Female, Heart Diseases, Humans, Male, Mutation, Pakistan, Pedigree, Prognosis, Sinoatrial Node}, issn = {1435-232X}, doi = {10.1038/s10038-018-0542-8}, author = {Liaqat, Khurram and Schrauwen, Isabelle and Raza, Syed Irfan and Lee, Kwanghyuk and Hussain, Shabir and Chakchouk, Imen and Nasir, Abdul and Acharya, Anushree and Abbe, Izoduwa and Umair, Muhammad and Ansar, Muhammad and Ullah, Irfan and Shah, Khadim and Bamshad, Michael J and Nickerson, Deborah A and Ahmad, Wasim and Leal, Suzanne M} } @article {596, title = {Whole-Exome Sequencing Enables a Precision Medicine Approach for Kidney Transplant Recipients.}, journal = {J Am Soc Nephrol}, volume = {30}, year = {2019}, month = {2019 02}, pages = {201-215}, abstract = {

BACKGROUND: Whole-exome sequencing (WES) finds a CKD-related mutation in approximately 20\% of patients presenting with CKD before 25 years of age. Although provision of a molecular diagnosis could have important implications for clinical management, evidence is lacking on the diagnostic yield and clinical utility of WES for pediatric renal transplant recipients.

METHODS: To determine the diagnostic yield of WES in pediatric kidney transplant recipients, we recruited 104 patients who had received a transplant at Boston Children{\textquoteright}s Hospital from 2007 through 2017, performed WES, and analyzed results for likely deleterious variants in approximately 400 genes known to cause CKD.

RESULTS: By WES, we identified a genetic cause of CKD in 34 out of 104 (32.7\%) transplant recipients. The likelihood of detecting a molecular genetic diagnosis was highest for patients with urinary stone disease (three out of three individuals), followed by renal cystic ciliopathies (seven out of nine individuals), steroid-resistant nephrotic syndrome (nine out of 21 individuals), congenital anomalies of the kidney and urinary tract (ten out of 55 individuals), and chronic glomerulonephritis (one out of seven individuals). WES also yielded a molecular diagnosis for four out of nine individuals with ESRD of unknown etiology. The WES-related molecular genetic diagnosis had implications for clinical care for five patients.

CONCLUSIONS: Nearly one third of pediatric renal transplant recipients had a genetic cause of their kidney disease identified by WES. Knowledge of this genetic information can help guide management of both transplant patients and potential living related donors.

}, keywords = {Adolescent, Boston, Child, Child, Preschool, Cohort Studies, Female, Genetic Predisposition to Disease, Genetic Testing, Graft Rejection, Graft Survival, Hospitals, Pediatric, Humans, Kidney Transplantation, Male, Precision Medicine, Prognosis, Renal Insufficiency, Chronic, Retrospective Studies, Risk Assessment, Severity of Illness Index, Survival Analysis, Transplant Recipients, Treatment Outcome, Whole Exome Sequencing}, issn = {1533-3450}, doi = {10.1681/ASN.2018060575}, author = {Mann, Nina and Braun, Daniela A and Amann, Kassaundra and Tan, Weizhen and Shril, Shirlee and Connaughton, Dervla M and Nakayama, Makiko and Schneider, Ronen and Kitzler, Thomas M and van der Ven, Amelie T and Chen, Jing and Ityel, Hadas and Vivante, Asaf and Majmundar, Amar J and Daga, Ankana and Warejko, Jillian K and Lovric, Svjetlana and Ashraf, Shazia and Jobst-Schwan, Tilman and Widmeier, Eugen and Hugo, Hannah and Mane, Shrikant M and Spaneas, Leslie and Somers, Michael J G and Ferguson, Michael A and Traum, Avram Z and Stein, Deborah R and Baum, Michelle A and Daouk, Ghaleb H and Lifton, Richard P and Manzi, Shannon and Vakili, Khashayar and Kim, Heung Bae and Rodig, Nancy M and Hildebrandt, Friedhelm} } @article {441, title = {Whole exome sequencing frequently detects a monogenic cause in early onset nephrolithiasis and~nephrocalcinosis.}, journal = {Kidney Int}, volume = {93}, year = {2018}, month = {2018 01}, pages = {204-213}, abstract = {

The incidence of nephrolithiasis continues to rise. Previously, we showed that a monogenic cause could be detected in 11.4\% of individuals with adult-onset nephrolithiasis or nephrocalcinosis and in 16.7-20.8\% of individuals with onset before 18 years of age, using gene panel sequencing of 30 genes known to cause nephrolithiasis/nephrocalcinosis. To overcome the limitations of panel sequencing, we utilized whole exome sequencing in 51 families, who presented before age 25 years with at least one renal stone or with a renal ultrasound finding of nephrocalcinosis to identify the underlying molecular genetic cause of disease. In 15 of 51 families, we detected a monogenic causative mutation by whole exome sequencing. A mutation in seven recessive genes (AGXT, ATP6V1B1, CLDN16, CLDN19, GRHPR, SLC3A1, SLC12A1), in one dominant gene (SLC9A3R1), and in one gene (SLC34A1) with both recessive and dominant inheritance was detected. Seven of the 19 different mutations were not previously described as disease-causing. In one family, a causative mutation in one of 117 genes that may represent phenocopies of nephrolithiasis-causing genes was detected. In nine of 15 families, the genetic diagnosis may have specific implications for stone management and prevention. Several factors that correlated with the higher detection rate in our cohort were younger age at onset of nephrolithiasis/nephrocalcinosis, presence of multiple affected members in a family, and presence of consanguinity. Thus, we established whole exome sequencing as an efficient approach toward a molecular genetic diagnosis in individuals with nephrolithiasis/nephrocalcinosis who manifest before age 25 years.

}, keywords = {Adolescent, Age of Onset, Child, Child, Preschool, Disease Progression, Female, Genetic Association Studies, Genetic Markers, Genetic Predisposition to Disease, Heredity, Humans, Infant, Male, Mutation, Nephrocalcinosis, Nephrolithiasis, Pedigree, Phenotype, Predictive Value of Tests, Prognosis, Risk Factors, Tomography, X-Ray Computed, Ultrasonography, Whole Exome Sequencing, Young Adult}, issn = {1523-1755}, doi = {10.1016/j.kint.2017.06.025}, author = {Daga, Ankana and Majmundar, Amar J and Braun, Daniela A and Gee, Heon Yung and Lawson, Jennifer A and Shril, Shirlee and Jobst-Schwan, Tilman and Vivante, Asaf and Schapiro, David and Tan, Weizhen and Warejko, Jillian K and Widmeier, Eugen and Nelson, Caleb P and Fathy, Hanan M and Gucev, Zoran and Soliman, Neveen A and Hashmi, Seema and Halbritter, Jan and Halty, Margarita and Kari, Jameela A and El-Desoky, Sherif and Ferguson, Michael A and Somers, Michael J G and Traum, Avram Z and Stein, Deborah R and Daouk, Ghaleb H and Rodig, Nancy M and Katz, Avi and Hanna, Christian and Schwaderer, Andrew L and Sayer, John A and Wassner, Ari J and Mane, Shrikant and Lifton, Richard P and Milosevic, Danko and Tasic, Velibor and Baum, Michelle A and Hildebrandt, Friedhelm} } @article {427, title = {Identification of STAC3 variants in non-Native American families with overlapping features of Carey-Fineman-Ziter syndrome and Moebius syndrome.}, journal = {Am J Med Genet A}, volume = {173}, year = {2017}, month = {2017 Oct}, pages = {2763-2771}, abstract = {

Horstick et al. (2013) previously reported a homozygous p.Trp284Ser variant in STAC3 as the cause of Native American myopathy (NAM) in 5 Lumbee Native American families with congenital hypotonia and weakness, cleft palate, short stature, ptosis, kyphoscoliosis, talipes deformities, and susceptibility to malignant hyperthermia (MH). Here we present two non-Native American families, who were found to have STAC3 pathogenic variants. The first proband and her affected older sister are from a consanguineous Qatari family with a suspected clinical diagnosis of Carey-Fineman-Ziter syndrome (CFZS) based on features of hypotonia, myopathic facies with generalized weakness, ptosis, normal extraocular movements, cleft palate, growth delay, and kyphoscoliosis. We identified the homozygous c.851G>C;p.Trp284Ser variant in STAC3 in both sisters. The second proband and his affected sister are from a non-consanguineous, Puerto Rican family who was evaluated for a possible diagnosis of Moebius syndrome (MBS). His features included facial and generalized weakness, minimal limitation of horizontal gaze, cleft palate, and hypotonia, and he has a history of MH. The siblings were identified to be compound heterozygous for STAC3 variants c.851G>C;p.Trp284Ser and c.763_766delCTCT;p.Leu255IlefsX58. Given the phenotypic overlap of individuals with CFZS, MBS, and NAM, we screened STAC3 in 12 individuals diagnosed with CFZS and in 50 individuals diagnosed with MBS or a congenital facial weakness disorder. We did not identify any rare coding variants in STAC3. NAM should be considered in patients presenting with facial and generalized weakness, normal or mildly abnormal extraocular movement, hypotonia, cleft palate, and scoliosis, particularly if there is a history of MH.

}, keywords = {Adaptor Proteins, Signal Transducing, Adolescent, Adult, Child, Female, Humans, Male, Mobius Syndrome, Muscular Diseases, Mutation, Pedigree, Pierre Robin Syndrome, Prognosis, Young Adult}, issn = {1552-4833}, doi = {10.1002/ajmg.a.38375}, author = {Telegrafi, Aida and Webb, Bryn D and Robbins, Sarah M and Speck-Martins, Carlos E and FitzPatrick, David and Fleming, Leah and Redett, Richard and Dufke, Andreas and Houge, Gunnar and van Harssel, Jeske J T and Verloes, Alain and Robles, Angela and Manoli, Irini and Engle, Elizabeth C and Jabs, Ethylin W and Valle, David and Carey, John and Hoover-Fong, Julie E and Sobreira, Nara L M} } @article {61, title = {Somatic Mutations in NEK9 Cause Nevus Comedonicus.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 May 05}, pages = {1030-1037}, abstract = {

Acne vulgaris (AV) affects most adolescents, and of those affected, moderate to severe disease occurs in 20\%. Comedones, follicular plugs consisting of desquamated keratinocytes and sebum, are central to its pathogenesis. Despite high heritability in first-degree relatives, AV genetic determinants remain incompletely understood. We therefore employed whole-exome sequencing (WES) in nevus comedonicus (NC), a rare disorder that features comedones and inflammatory acne cysts in localized, linear configurations. WES identified somatic NEK9 mutations, each affecting highly conserved residues within its kinase or RCC1 domains, in affected tissue of three out of three NC-affected subjects. All mutations are gain of function, resulting in increased phosphorylation at Thr210, a hallmark of NEK9 kinase activation. We found that comedo formation in NC is marked by loss of follicular differentiation markers, expansion of keratin-15-positive cells from localization within the bulge to the entire sub-bulge follicle and cyst, and ectopic expression of keratin 10, a marker of interfollicular differentiation not present in normal follicles. These findings suggest that NEK9 mutations in NC disrupt normal follicular differentiation and identify NEK9 as a potential regulator of follicular homeostasis.

}, keywords = {Adolescent, Adult, Child, Female, Fluorescent Antibody Technique, High-Throughput Nucleotide Sequencing, Humans, Male, Mutation, Nevus, NIMA-Related Kinases, Prognosis, Skin Neoplasms, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.03.019}, author = {Levinsohn, Jonathan L and Sugarman, Jeffrey L and McNiff, Jennifer M and Antaya, Richard J and Choate, Keith A} } @article {122, title = {Allelic Mutations of KITLG, Encoding KIT Ligand, Cause Asymmetric and Unilateral Hearing Loss and Waardenburg Syndrome Type 2.}, journal = {Am J Hum Genet}, volume = {97}, year = {2015}, month = {2015 Nov 05}, pages = {647-60}, abstract = {

Linkage analysis combined with whole-exome sequencing in a large family with congenital and stable non-syndromic unilateral and asymmetric hearing loss (NS-UHL/AHL) revealed a heterozygous truncating mutation, c.286_303delinsT (p.Ser96Ter), in KITLG. This mutation co-segregated with NS-UHL/AHL as a dominant trait with reduced penetrance. By screening a panel of probands with NS-UHL/AHL, we found an additional mutation, c.200_202del (p.His67_Cys68delinsArg). In~vitro studies revealed that the p.His67_Cys68delinsArg transmembrane isoform of KITLG is not detectable at the cell membrane, supporting pathogenicity. KITLG encodes a ligand for the KIT receptor. Also, KITLG-KIT signaling and MITF are suggested to mutually interact in melanocyte development. Because mutations in MITF are causative of Waardenburg syndrome type 2 (WS2), we screened KITLG in suspected WS2-affected probands. A heterozygous missense mutation, c.310C>G (p.Leu104Val), that segregated with WS2 was identified in a small family. In~vitro studies revealed that the p.Leu104Val transmembrane isoform of KITLG is located at the cell membrane, as is wild-type KITLG. However, in culture media of transfected cells, the p.Leu104Val soluble isoform of KITLG was reduced, and no soluble p.His67_Cys68delinsArg and p.Ser96Ter KITLG could be detected. These data suggest that mutations in KITLG associated with NS-UHL/AHL have a loss-of-function effect. We speculate that the mechanism of the mutation underlying WS2 and leading to membrane incorporation and reduced secretion of KITLG occurs via a dominant-negative or gain-of-function effect. Our study unveils different phenotypes associated with KITLG, previously associated with pigmentation abnormalities, and will thereby improve the genetic counseling given to individuals with KITLG variants.

}, keywords = {Alleles, Animals, Female, Fluorescent Antibody Technique, Genetic Linkage, Hearing Loss, Unilateral, Humans, Male, Mice, Mutation, NIH 3T3 Cells, Pedigree, Phenotype, Prognosis, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Stem Cell Factor, Waardenburg Syndrome}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.09.011}, author = {Zazo Seco, Celia and Serr{\~a}o de Castro, Luciana and van Nierop, Josephine W and Mor{\'\i}n, Mat{\'\i}as and Jhangiani, Shalini and Verver, Eva J J and Schraders, Margit and Maiwald, Nadine and Wesdorp, Mieke and Venselaar, Hanka and Spruijt, Liesbeth and Oostrik, Jaap and Schoots, Jeroen and van Reeuwijk, Jeroen and Lelieveld, Stefan H and Huygen, Patrick L M and Insenser, Mar{\'\i}a and Admiraal, Ronald J C and Pennings, Ronald J E and Hoefsloot, Lies H and Arias-V{\'a}squez, Alejandro and de Ligt, Joep and Yntema, Helger G and Jansen, Joop H and Muzny, Donna M and Huls, Gerwin and van Rossum, Michelle M and Lupski, James R and Moreno-Pelayo, Miguel Angel and Kunst, Henricus P M and Kremer, Hannie} } @article {120, title = {Nonrecurrent 17p11.2p12 Rearrangement Events that Result in Two Concomitant Genomic Disorders: The PMP22-RAI1 Contiguous Gene Duplication Syndrome.}, journal = {Am J Hum Genet}, volume = {97}, year = {2015}, month = {2015 Nov 05}, pages = {691-707}, abstract = {

The genomic duplication associated with Potocki-Lupski syndrome (PTLS) maps in close proximity to the duplication associated with Charcot-Marie-Tooth disease type 1A (CMT1A). PTLS is characterized by hypotonia, failure to thrive, reduced body weight, intellectual disability, and autistic features. CMT1A is a common autosomal dominant distal symmetric peripheral polyneuropathy. The key dosage-sensitive genes RAI1 and PMP22 are respectively associated with PTLS and CMT1A. Recurrent duplications accounting for the majority of subjects with these conditions are mediated by nonallelic homologous recombination between distinct low-copy repeat (LCR) substrates. The LCRs flanking a contiguous genomic interval encompassing both RAI1 and PMP22 do not share extensive homology; thus, duplications encompassing both loci are rare and potentially generated by a different mutational mechanism. We characterized genomic rearrangements that simultaneously duplicate PMP22 and RAI1, including nine potential complex genomic rearrangements, in 23 subjects by high-resolution array comparative genomic hybridization and breakpoint junction sequencing. Insertions and microhomologies were found at the breakpoint junctions, suggesting potential replicative mechanisms for rearrangement formation. At the breakpoint junctions of these nonrecurrent rearrangements, enrichment of repetitive DNA sequences was observed, indicating that they might predispose to genomic instability and rearrangement. Clinical evaluation revealed blended PTLS and CMT1A phenotypes with a potential earlier onset of neuropathy. Moreover, additional clinical findings might be observed due to the extra duplicated material included in the rearrangements. Our genomic analysis suggests replicative mechanisms as a predominant mechanism underlying PMP22-RAI1 contiguous gene duplications and provides further evidence supporting the role of complex genomic architecture in genomic instability.

}, keywords = {Abnormalities, Multiple, Charcot-Marie-Tooth Disease, Child, Child, Preschool, Chromosome Disorders, Chromosome Duplication, Chromosomes, Human, Pair 17, Comparative Genomic Hybridization, Female, Follow-Up Studies, Gene Duplication, Gene Rearrangement, Genome, Human, Genomics, Humans, Infant, Male, Models, Genetic, Myelin Proteins, Phenotype, Prognosis, Recombination, Genetic, Transcription Factors}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.10.003}, author = {Yuan, Bo and Harel, Tamar and Gu, Shen and Liu, Pengfei and Burglen, Lydie and Chantot-Bastaraud, Sandra and Gelowani, Violet and Beck, Christine R and Carvalho, Claudia M B and Cheung, Sau Wai and Coe, Andrew and Malan, Val{\'e}rie and Munnich, Arnold and Magoulas, Pilar L and Potocki, Lorraine and Lupski, James R} } @article {158, title = {Successful diagnosis of HIBCH deficiency from exome sequencing and positive retrospective analysis of newborn screening cards in two siblings presenting with Leigh{\textquoteright}s disease.}, journal = {Mol Genet Metab}, volume = {115}, year = {2015}, month = {2015 Aug}, pages = {161-7}, abstract = {

PURPOSE: 3-Hydroxyisobutryl-CoA hydrolase (HIBCH) deficiency is a rare disorder of valine metabolism. We present a family with the oldest reported subjects with HIBCH deficiency and provide support that HIBCH deficiency should be included in the differential for elevated hydroxy-C4-carnitine in newborn screening (NBS).

METHODS: Whole exome sequencing (WES) was performed on one affected sibling. HIBCH enzymatic activity was measured in patient fibroblasts. Acylcarnitines were measured by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Disease incidence was estimated using a cohort of 61,434 individuals.

RESULTS: Two siblings presented with infantile-onset, progressive neurodegenerative disease. WES identified a novel homozygous variant in HIBCH c.196C>T; p.Arg66Trp. HIBCH enzymatic activity was significantly reduced in patients{\textquoteright} fibroblasts. Acylcarnitine analysis showed elevated hydroxy-C4-carnitine in blood spots of both affected siblings, including in their NBS cards, while plasma acylcarnitines were normal. Estimates show HIBCH deficiency incidence as high as 1 in ~130,000 individuals.

CONCLUSION: We describe a novel family with HIBCH deficiency at the biochemical, enzymatic and molecular level. Disease incidence estimates indicate HIBCH deficiency may be under-diagnosed. This together with the elevated hydroxy-C4-carnitine found in the retrospective analysis of our patient{\textquoteright}s NBS cards suggests that this disorder could be screened for by NBS programs and should be added to the differential diagnosis for elevated hydroxy-C4-carnitine which is already measured in most NBS programs using MS/MS.

}, keywords = {Abnormalities, Multiple, Adolescent, Amino Acid Metabolism, Inborn Errors, Carnitine, Child, Child, Preschool, Cohort Studies, Exome, Female, Fibroblasts, Humans, Infant, Infant, Newborn, Leigh Disease, Male, Mass Spectrometry, Neonatal Screening, Prognosis, Retrospective Studies, Sequence Analysis, DNA, Siblings, Thiolester Hydrolases}, issn = {1096-7206}, doi = {10.1016/j.ymgme.2015.05.008}, author = {Stiles, Ashlee R and Ferdinandusse, Sacha and Besse, Arnaud and Appadurai, Vivek and Leydiker, Karen B and Cambray-Forker, E J and Bonnen, Penelope E and Abdenur, Jose E} }