Clinical Focus


  • Clinical Genetics

Academic Appointments


Professional Education


  • Medical Education: Sidney Kimmel Medical College Thomas Jefferson University (2013) PA
  • Board Certification: American Board of Pediatrics, Pediatrics (2018)
  • Board Certification, American Board of Pediatrics, Pediatrics (2018)
  • Board Certification: American Board of Medical Genetics and Genomics, Clinical Genetics (2017)
  • Fellowship: Children's Hospital of Philadelphia (2017) PA
  • Residency: Children's Hospital of Philadelphia (2016) PA
  • Internship: Children's Hospital of Philadelphia (2014) PA

All Publications


  • Genomic sequencing in a cohort of individuals with fibular aplasia, tibial campomelia, and oligosyndactyly (FATCO) syndrome. American journal of medical genetics. Part A Matalon, D. R., Bhoj, E. J., Li, D., McDougall, C., Schindewolf, E., Khalek, N., Wilkens, A., McManus, M., Deardorff, M. A., Zackai, E. H. 2023

    Abstract

    Fibular aplasia, tibial campomelia, and oligosyndactyly (FATCO) syndrome (MIM 246570) is a rare disorder characterized by specific skeletal findings (fibular aplasia, shortened or bowed tibia, and oligosyndactyly of the foot and/or hand). Typically, no other anomalies, craniofacial dysmorphism, or developmental delays are associated. Here we report three unrelated individuals with limb anomalies consistent with FATCO syndrome who have been followed clinically for 5years. Genetic testing of previously reported individuals with FATCO syndrome has not revealed a genetic diagnosis. However, no broader sequencing approaches have been reported. We describe the results of the three individuals with FATCO syndrome from exome and genome sequencing, all of which was nondiagnostic. Our study suggests that FATCO syndrome is not the result of a simple monogenic etiology.

    View details for DOI 10.1002/ajmg.a.63105

    View details for PubMedID 36610046

  • DNA methylation episignature for Witteveen-Kolk syndrome due to SIN3A haploinsufficiency. Genetics in medicine : official journal of the American College of Medical Genetics Coenen-van der Spek, J., Relator, R., Kerkhof, J., McConkey, H., Levy, M. A., Tedder, M. L., Louie, R. J., Fletcher, R. S., Moore, H. W., Childers, A., Farrelly, E. R., Champaigne, N. L., Lyons, M. J., Everman, D. B., Rogers, R. C., Skinner, S. A., Renck, A., Matalon, D. R., Dills, S. K., Monteleone, B., Demirdas, S., Dingemans, A. J., Donker Kaat, L., Kolk, S. M., Pfundt, R., Rump, P., Sadikovic, B., Kleefstra, T., Butler, K. M. 2022

    Abstract

    PURPOSE: Witteveen-Kolk syndrome (WITKOS) is a rare, autosomal dominant neurodevelopmental disorder caused by heterozygous loss-of-function alterations in the SIN3A gene. WITKOS has variable expressivity that commonly overlaps with other neurodevelopmental disorders. In this study, we characterized a distinct DNA methylation epigenetic signature (episignature) distinguishing WITKOS from unaffected individuals as well as individuals with other neurodevelopmental disorders with episignatures and described 9 previously unpublished individuals with SIN3A haploinsufficiency.METHODS: We studied the phenotypic characteristics and the genome-wide DNA methylation in the peripheral blood samples of 20 individuals with heterozygous alterations in SIN3A. A total of 14 samples were used for the identification of the episignature and building of a predictive diagnostic biomarker, whereas the diagnostic model was used to investigate the methylation pattern of the remaining 6 samples.RESULTS: A predominantly hypomethylated DNA methylation profile specific to WITKOS was identified, and the classifier model was able to diagnose a previously unresolved test case. The episignature was sensitive enough to detect individuals with varying degrees of phenotypic severity carrying SIN3A haploinsufficient variants.CONCLUSION: We identified a novel, robust episignature in WITKOS due to SIN3A haploinsufficiency. This episignature has the potential to aid identification and diagnosis of individuals with WITKOS.

    View details for DOI 10.1016/j.gim.2022.10.004

    View details for PubMedID 36399132

  • Short Bones, Renal Stones, and Diagnostic Moans: Hypercalcemia in a Girl Found to Have Coffin-Lowry Syndrome. Journal of investigative medicine high impact case reports Tise, C. G., Matalon, D. R., Manning, M. A., Byers, H. M., Grover, M. 2022; 10: 23247096221101844

    Abstract

    Pathogenic variants in RPS6KA3 are associated with Coffin-Lowry syndrome (CLS), an X-linked semidominant disorder characterized by intellectual disability, stimulus-induced drop attacks, distinctive facial features, progressive kyphoscoliosis, and digit anomalies in hemizygous males. Heterozygous females may also have features of CLS; however, there can be considerable phenotypic variation, often attributed to ratios of X-inactivation in various tissue types. Although skeletal anomalies and short stature are hallmarks of CLS, hypercalcemia has not been reported. Here we describe a 30-month-old girl with gross motor delays, short stature, dysmorphic features, bilateral duplicated renal collecting systems, and no family history of hypercalcemia who required multiple admissions for idiopathic hypercalcemia necessitating bisphosphonate infusions at 12.5 and 15 months of age. A maternally inherited likely-pathogenic variant in RPS6KA3 was identified by trio exome sequencing, consistent with the diagnosis of CLS in the proband and her mother. Maternal history was notable only for decreased height compared to first-degree relatives, bilateral genu valgum, and a bicornuate uterus; she was later found to also have a partially duplicated left renal collecting system. Subsequent X-inactivation studies in blood aligned with the phenotypic variation between mother and daughter. Although hypercalcemia is not a reported feature in CLS, there is evidence of interrupted osteoblast differentiation, providing a potential mechanism for hypercalcemia in this genetic condition. The hypercalcemia in this case may represent a severe presentation of an unrecognized clinical feature in CLS that resolves with age. This case further highlights the intrafamilial phenotypic variation of CLS among females, suggesting X-inactivation as the underlying mechanism, and demonstrates the value of exome sequencing in patients for whom a genetic disorder is highly suspected but not identified despite thorough evaluation.

    View details for DOI 10.1177/23247096221101844

    View details for PubMedID 35638718

  • Loss-of-function variants in SRRM2 cause a neurodevelopmental disorder. Genetics in medicine : official journal of the American College of Medical Genetics Cuinat, S., Nizon, M., Isidor, B., Stegmann, A., van Jaarsveld, R. H., van Gassen, K. L., van der Smagt, J. J., Volker-Touw, C. M., Holwerda, S. J., Terhal, P. A., Schuhmann, S., Vasileiou, G., Khalifa, M., Nugud, A. A., Yasaei, H., Ousager, L. B., Brasch-Andersen, C., Deb, W., Besnard, T., Simon, M. E., Amsterdam, K. H., Verbeek, N. E., Matalon, D., Dykzeul, N., White, S., Spiteri, E., Devriendt, K., Boogaerts, A., Willemsen, M., Brunner, H. G., Sinnema, M., De Vries, B. B., Gerkes, E. H., Pfundt, R., Izumi, K., Krantz, I. D., Xu, Z. L., Murrell, J. R., Valenzuela, I., Cusco, I., Rovira-Moreno, E., Yang, Y., Bizaoui, V., Patat, O., Faivre, L., Tran-Mau-Them, F., Vitobello, A., Denommé-Pichon, A. S., Philippe, C., Bezieau, S., Cogné, B. 2022

    Abstract

    SRRM2 encodes the SRm300 protein, a splicing factor of the SR-related protein family characterized by its serine- and arginine-enriched domains. It promotes interactions between messenger RNA and the spliceosome catalytic machinery. This gene, predicted to be highly intolerant to loss of function (LoF) and very conserved through evolution, has not been previously reported in constitutive human disease.Among the 1000 probands studied with developmental delay and intellectual disability in our database, we found 2 patients with de novo LoF variants in SRRM2. Additional families were identified through GeneMatcher.Here, we report on 22 patients with LoF variants in SRRM2 and provide a description of the phenotype. Molecular analysis identified 12 frameshift variants, 8 nonsense variants, and 2 microdeletions of 66 kb and 270 kb. The patients presented with a mild developmental delay, predominant speech delay, autistic or attention-deficit/hyperactivity disorder features, overfriendliness, generalized hypotonia, overweight, and dysmorphic facial features. Intellectual disability was variable and mild when present.We established SRRM2 as a gene responsible for a rare neurodevelopmental disease.

    View details for DOI 10.1016/j.gim.2022.04.011

    View details for PubMedID 35567594

  • Reuben Matalon, MD, PhD, FACMG (1935-2021). Human gene therapy Matalon, D. R., Velagaleti, G., Ahmed, S. S., Gessler, D. J., Gao, G. 2022

    View details for DOI 10.1089/hum.2022.29202.drm

    View details for PubMedID 35244486

  • Leiomyomatosis in an Infant With a SUFU Splice Site Variant: Case Report. Journal of pediatric hematology/oncology Rao, R. R., Dulken, B. W., Matalon, D. R., Borensztein, M., McGuinness, M., Cizek, S. M., Bruzoni, M., Tan, S. Y., Kreimer, S. 2022

    Abstract

    Heterozygous loss-of-function variants in the suppressor of fused protein gene (SUFU) can result in Gorlin syndrome, which is characterized by an increased frequency of basal cell carcinoma, medulloblastoma, odontogenic keratocysts, as well as other tumors. We describe a case of a 5-month-old female who presented with multiple intra-abdominal leiomyomata and was found to have a likely pathogenic splice site variant in the SUFU gene. This is the first reported case of leiomyomatosis secondary to a pathogenic SUFU variant in an infant and may represent an early, atypical presentation of Gorlin syndrome.

    View details for DOI 10.1097/MPH.0000000000002454

    View details for PubMedID 35398865

  • Points to consider to avoid unfair discrimination and the misuse of genetic information: A statement of the American College of Medical Genetics and Genomics (ACMG). Genetics in medicine : official journal of the American College of Medical Genetics Seaver, L. H., Khushf, G., King, N. M., Matalon, D. R., Sanghavi, K., Vatta, M., Wees, K., ACMG Social, E. a. 2022; 24 (3): 512-520

    View details for DOI 10.1016/j.gim.2021.11.002

    View details for PubMedID 35253645

  • Clinical and molecular characterization of five new individuals with WAC-related intellectual disability: Evidence of pathogenicity for a novel splicing variant. American journal of medical genetics. Part A Morales, J. A., Valenzuela, I., Cusco, I., Cogne, B., Isidor, B., Matalon, D. R., Gomez-Ospina, N. 1800

    Abstract

    WAC-related intellectual disability (ID) is a rare genetic condition characterized by a spectrum of neurodevelopmental disorders of varying severity, including global developmental delay (GDD), ID, and autism spectrum disorder. Here, we describe five affected individuals, age range 9-20years, and provide proof of pathogenicity of a novel splicing variant. All individuals presented with GDD, some degree of ID, and variable dysmorphism. Except for feeding difficulties, all patients were healthy without major congenital malformations or medical comorbidities. All individuals were heterozygous for de novo, previously unreported, loss of function variants in WAC. Three unrelated patients from different ethnic backgrounds shared the intronic variant c.381+4_381+7delAGTA, which was predicted to alter splicing and was initially classified as a variant of uncertain significance. Reverse transcription-polymerase chain reaction analysis from one patient's cells confirmed aberrant splicing of the WAC transcript resulting in premature termination and a truncated protein p.(Gly92Alafs*2). These functional studies and the identification of several nonrelated individuals provide sufficient evidence to classify this variant as pathogenic. The clinical description of these five individuals and the three novel variants expand the genotypic and phenotypic spectrum of this ultrarare disease.

    View details for DOI 10.1002/ajmg.a.62648

    View details for PubMedID 35018708

  • Congenital polyvalvular disease expands the cardiac phenotype of the RASopathies. American journal of medical genetics. Part A Matalon, D. R., Stevenson, D. A., Bhoj, E. J., Santani, A. B., Keena, B. n., Cohen, M. S., Lin, A. E., Sheppard, S. E., Zackai, E. H. 2021

    Abstract

    The RASopathies are a group of similar genetic syndromes with cardiovascular abnormalities, characteristic facial features, short stature, abnormalities of the skin and musculoskeletal system, and variable neurodevelopmental challenges. The most common cardiovascular abnormalities include pulmonary valvular stenosis and hypertrophic cardiomyopathy. Congenital polyvalvular disease (CPVD) refers to congenital dysplasia of two or more cardiac valves. We diagnosed a RASopathy in two individuals with CPVD and noted that CPVD in RASopathies has rarely been reported in the literature. Thus, we performed a retrospective chart review and literature review to investigate the association and characterize the phenotype of CPVD in the RASopathies. CPVD was present in 2.5% (n = 6/243) of individuals in our RASopathy cohort. Involvement of two cardiac valves, commonly the aortic and pulmonic valves, was seen in the majority of individuals (6/8; 75%) in our cohort, but only 27% (3/11) of reported CPVD and RASopathy cases in the literature. CPVD should be considered an associated cardiovascular phenotype of the RASopathies, which has implications for diagnosis and management.

    View details for DOI 10.1002/ajmg.a.62146

    View details for PubMedID 33683002

  • Diagnostic journey and impact of enzyme replacement therapy for mucopolysaccharidosis IVA: a sibling control study. Orphanet journal of rare diseases Ficicioglu, C. n., Matalon, D. R., Luongo, N. n., Menello, C. n., Kornafel, T. n., Degnan, A. J. 2020; 15 (1): 336

    Abstract

    Mucopolysaccharidosis (MPS) IVA, also known as Morquio A syndrome, is a rare autosomal recessive lysosomal storage disorder caused by a deficiency in the enzyme N-acetylgalactosamine-6-sulfatase. Early recognition, diagnosis, and treatment of this progressive, multisystem disease by enzyme replacement therapy (ERT) can lead to improved outcomes and reduced mortality.This report documents the diagnostic journey and treatment with ERT of three siblings with MPS IVA. Clinical outcome measures included growth, endurance, imaging, cardiac, respiratory, ophthalmology, and laboratory evaluations.Three siblings, diagnosed at 14.7, 10.1, and 3.2 years of age, demonstrated clinical improvement with weekly infusions of 2.0 mg/kg elosulfase alfa (Vimizim®, BioMarin Pharmaceutical, Novato, CA, USA). Patient 1 (oldest sibling) and Patient 2 (middle sibling) experienced a diagnostic delay of 8 years 7 months and 4 years after symptom onset, respectively. All three patients demonstrated improvements in growth, 6-min walk distance, joint range of motion, and respiratory function after 30 months of ERT. The treatment was well tolerated without any adverse events.This case series highlights the importance of early recognition of the clinical and imaging findings that are initially subtle in MPS IVA. Early treatment with ERT is necessary to slow irreversible disease progression and improve patient outcomes. The oldest sibling experienced improvements in mobility despite severe symptoms resulting from a late diagnosis. When evaluating patients with skeletal anomalies, imaging multiple body regions is recommended. When findings such as anterior beaking of vertebrae or bilateral femoral head dysplasia are present, MPS IVA should be included in the differential diagnosis. Newborn screening must be considered for early detection, accurate diagnosis, and initiation of treatment to reduce morbidity.

    View details for DOI 10.1186/s13023-020-01618-y

    View details for PubMedID 33256811

  • De novo variants in SUPT16H cause neurodevelopmental disorders associated with corpus callosum abnormalities. Journal of medical genetics Bina, R. n., Matalon, D. n., Fregeau, B. n., Tarsitano, J. J., Aukrust, I. n., Houge, G. n., Bend, R. n., Warren, H. n., Stevenson, R. E., Stuurman, K. E., Barkovich, A. J., Sherr, E. H. 2020

    Abstract

    Whole-exome sequencing (WES) has identified de novo variants in chromatin remodelling genes in patients with neurodevelopmental disorders (NDD). We report on a novel genetic discovery in chromatin remodelling in patients with NDD who also have corpus callosum (CC) anomalies.To discover novel genes linked to both CC anomalies and NDD.Clinical WES was performed for evaluation of NDD, identifying five patients with de novo variants in SUPT16H, a subunit of the FACT (facilitates chromatin transcription) complex. The clinical phenotypes, genetic results and brain MRIs were obtained and systematically reviewed. In silico protein function predictions were assessed and allele frequencies in control populations were compared.We identified four patients with de novo missense variants in SUPT16H and one patient with a de novo deletion including SUPT16H. These variants were not reported in the updated Genome Aggregation Database. When assayable, all protein products were predicted to be damaging. Symptoms included intellectual disability, autistic features, minor dysmorphic features and seizures. Anomalies of the CC were seen in all three patients with available brain imaging.Our findings implicate the gene SUPT16H in a novel disorder characterised by neurodevelopmental deficits and CC anomalies.

    View details for DOI 10.1136/jmedgenet-2019-106193

    View details for PubMedID 31924697

  • ClinPhen extracts and prioritizes patient phenotypes directly from medical records to expedite genetic disease diagnosis GENETICS IN MEDICINE Deisseroth, C. A., Birgmeier, J., Bodle, E. E., Kohler, J. N., Matalon, D. R., Nazarenko, Y., Genetti, C. A., Brownstein, C. A., Schmitz-Abe, K., Schoch, K., Cope, H., Signer, R., Network, U., Martinez-Agosto, J. A., Shashi, V., Beggs, A. H., Wheeler, M. T., Bernstein, J. A., Bejerano, G. 2019; 21 (7): 1585–93
  • LOCALIZING NEUROLOGIC FEATURES AT PRESENTATION OF VLCAD DEFICIENCY Leahy, P., Matalon, D., Ruzhnikov, M., Cowan, T., Enns, G. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2019: 282
  • Paraspinal Atrophy Suggesting Underlying Genetic Etiology Schwartz, D., Fong, J., Matalon, D., Wong, J., Greene, M. LIPPINCOTT WILLIAMS & WILKINS. 2019
  • LOCALIZING NEUROLOGIC FEATURES AT PRESENTATION OF VLCAD DEFICIENCY Leahy, P., Matalon, D., Ruzhnikov, M., Cowan, T., Enns, G. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2019: 311
  • THE DIAGNOSIS AND NATURAL HISTORY OF THE MUCOPOLYSACCHARIDOSIS IVA IN ONE FAMILY Matalon, D. R., Dougherty, P., Lulis, L., Medne, L., Krantz, I., Yum, S., Ficicioglu, C. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2018: 249–50
  • The diagnosis and natural history of mucopolysaccharidosis type IVA in one family Matalon, D., Dougherty, P., Lulis, L., Medne, L., Krantz, I., Yum, S., Ficicioglu, C. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2018: S92
  • ClinPhen extracts and prioritizes patient phenotypes directly from medical records to expedite genetic disease diagnosis. Genetics in medicine : official journal of the American College of Medical Genetics Deisseroth, C. A., Birgmeier, J. n., Bodle, E. E., Kohler, J. N., Matalon, D. R., Nazarenko, Y. n., Genetti, C. A., Brownstein, C. A., Schmitz-Abe, K. n., Schoch, K. n., Cope, H. n., Signer, R. n., Martinez-Agosto, J. A., Shashi, V. n., Beggs, A. H., Wheeler, M. T., Bernstein, J. A., Bejerano, G. n. 2018

    Abstract

    Diagnosing monogenic diseases facilitates optimal care, but can involve the manual evaluation of hundreds of genetic variants per case. Computational tools like Phrank expedite this process by ranking all candidate genes by their ability to explain the patient's phenotypes. To use these tools, busy clinicians must manually encode patient phenotypes from lengthy clinical notes. With 100 million human genomes estimated to be sequenced by 2025, a fast alternative to manual phenotype extraction from clinical notes will become necessary.We introduce ClinPhen, a fast, high-accuracy tool that automatically converts clinical notes into a prioritized list of patient phenotypes using Human Phenotype Ontology (HPO) terms.ClinPhen shows superior accuracy and 20× speedup over existing phenotype extractors, and its novel phenotype prioritization scheme improves the performance of gene-ranking tools.While a dedicated clinician can process 200 patient records in a 40-hour workweek, ClinPhen does the same in 10 minutes. Compared with manual phenotype extraction, ClinPhen saves an additional 3-5 hours per Mendelian disease diagnosis. Providers can now add ClinPhen's output to each summary note attached to a filled testing laboratory request form. ClinPhen makes a substantial contribution to improvements in efficiency critically needed to meet the surging demand for clinical diagnostic sequencing.

    View details for PubMedID 30514889