Dopa decarboxylase (DDC) is a crucial enzyme that regulates melanin synthesis and plays an essential role in cuticular pigmentation and insect development. However, the function of DDC in the fall armyworm, Spodoptera frugiperda, is not yet well understood. In this study, we knocked out the DDC gene and found that mosaic mutants displayed an albino phenotype across all life stages, including larval, pupal, and adult stages. Notably, homozygous DDC mutants showed complete larval albinism, exhibited developmental delays, and frequently failed to pupate, ultimately leading to death. Histological analyses revealed that tissue remodeling during metamorphosis was disrupted and became disorganized. A few individuals survived to adulthood, but they developed severely curled forewings. To clarify the molecular basis of these phenotypes, we performed a transcriptomic analysis and found that DDC influences pigmentation by regulating melanin-related and pteridine-related metabolic pathways. Additionally, DDC disruption altered the expression of genes involved in chitin metabolism and cuticular proteins, and affected the juvenile hormone and ecdysone signaling pathways. Overall, these results provide the first evidence that DDC is critical for pigmentation and development in S. frugiperda and shed new light on the molecular mechanisms underlying body color formation.

The CRISPR-Cas9 dopa decarboxylase (DDC) gene knockout SH-SY5Y model for aromatic L-amino acid decarboxylase (AADC) deficiency provides a valuable neuronal platform for functional and structural investigation of pathogenic variants. In their study, Bertoldi etal. successfully recapitulate the biochemical and metabolic hallmarks of AADC deficiency using the AADC catalytic variants R347Q and L353P. Their combined structural and cellular approach identifies loop3 dynamics as a critical determinant of enzymatic dysfunction. This model may pave the way for the development of precision therapies.

DOPA decarboxylase (DDC) plays a crucial role in the physiological functions of animals by participating in the dopaminergic system. However, the functions of DDC in shellfish remain poorly understood. The Pacific oyster (Crassostrea gigas) is an extensively cultivated shellfish. In this study, we characterized a DDC gene, designated CgDDC, from C. gigas. The CgDDC gene encodes a protein that contains a Pyridoxal_deC domain, which features specific binding sites for pyridoxal-5'-phosphate (PLP) and L-DOPA. CgDDC exhibits a significantly higher expression level in the black shell oyster strain than the white strain. In vitro enzymatic reaction assays demonstrated that CgDDC catalyzes the conversion of L-DOPA to dopamine. In vivo experiments revealed that inhibiting CgDDC activity reduced the expression of genes associated with tyrosine metabolism. Furthermore, the knockdown of CgDDC caused a decline in cAMP level and reduced transcription of genes involved in the cAMP-mediated melanogenesis. Additionally, treatment with L-α-DOPA inhibited CgDDC enzyme activity and cAMP-mediated melanogenesis; however, dopamine supplementation countered this inhibition, maintaining gene expression and melanin content at baseline levels. Collectively, our findings suggest that CgDDC is intricately involved in regulating tyrosine metabolism and melanogenesis in C. gigas.

Lineage-specific duplication and functional diversification of DOPA-decarboxylase genes in the Gryllidae family, as revealed in Gryllus bimaculatus.

Background: The main objective of this prospective, multicenter study (REVEAL-CP) was to test children with cerebral palsy-like signs and symptoms for raised 3-O-methyldopa (3-OMD) blood levels, a biomarker for aromatic L-amino acid decarboxylase deficiency (AADCd). A secondary objective was to characterize the molecular basis for the defective aromatic L-amino acid decarboxylase (AADC) gene product. Methods: Patients were identified in pediatric secondary and tertiary care hospitals through database searches and personal communication. 3-OMD concentrations from Guthrie card tests were determined using liquid chromatography/mass spectrometry. If 3-OMD was raised, cerebrospinal fluid analysis and dopa decarboxylase (DDC) gene sequencing were performed. An in-silico mutagenesis analysis was carried out to model altered AADC enzymes. Results: In total, 166 patients were enrolled in this study. The median age was 8 years. Sixty-six patients (39.8%) had a diagnosis of cerebral palsy, with the most common type being "mixed" (n = 42; 25.3%). One patient (0.6%), an 11-month-old boy from Italy, was diagnosed with AADCd caused by a homozygous, pathogenic DDC variant (c.749C>T; p.Ser250Phe). Three-dimensional modeling of the Ser250Phe AADC enzyme variant revealed its destabilization. Conclusions: A Guthrie card test for 3-OMD is a recognized screening technique for AADCd. If universal newborn screening for this metabolic disease is not available, children with signs and symptoms of a movement disorder should be investigated for AADCd.

The present study investigates the neuroprotective effects of the sea urchin Paracentrotus lividus gonadal extract on rotenone-induced neurotoxicity in a Parkinson's disease (PD) rat model. Parkinson's disease, characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN), is exacerbated by oxidative stress and neuroinflammation. The study involved fifty Wistar rats divided into five groups: control, dimethyl sulfoxide (DMSO) control, Paracentrotus lividus gonadal extract-treated, rotenone-treated, and combined rotenone with Paracentrotus lividus gonadal extract-treated. Behavioral assessments included the rotarod and open field tests, while biochemical analyses measured oxidative stress markers (malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH)), antioxidants (superoxide dismutase (SOD), catalase (CAT)), pro-inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)), and neurotransmitters (dopamine (DA), levodopa (L-Dopa)). Histological and immunohistochemical analyses evaluated the neuronal integrity and tyrosine hydroxylase (TH) and alpha-synuclein expression. The results showed that Paracentrotus lividus gonadal extract significantly mitigated rotenone-induced motor deficits and improved locomotor activity. Biochemically, the extract reduced oxidative stress and inflammation markers while enhancing antioxidant levels. Histologically, it restored neuronal integrity and reduced alpha-synuclein accumulation. Molecularly, it increased tyrosine hydroxylase and dopa decarboxylase gene expression, essential for dopamine synthesis. These findings suggest that Paracentrotus lividus gonadal extract exerts neuroprotective effects by modulating oxidative stress, neuroinflammation, and dopaminergic neuron integrity, highlighting its potential as a therapeutic agent for Parkinson's disease.

Investigating the Correlation between Dopa Decarboxylase (DDC) and Dopamine Beta-Hydroxylase (DBH) genes Expression in Parkinson's and schizophrenia patients

Newborn screening for aromatic l-amino acid decarboxylase deficiency – Strategies, results, and implication for prevalence calculations

Abstract BackgroundAromatic ʟ‐amino acid decarboxylase (AADC) deficiency is a rare, severe neurological disorder caused by pathogenic variants in the dopa decarboxylase (DDC) gene, resulting in a combined deficiency of monoamine neurotransmitters. Clinically, patients present with a range of dysfunctions that impact motor, autonomic, and cognitive development. The constellation of symptoms of AADC deficiency varies among patients, and clinical presentation falls across a wide spectrum. However, most patients with AADC deficiency experience significant impairments when compared with children with normal development, irrespective of genotype, phenotype, or disease severity. Further, AADC deficiency is associated with increased mortality.MethodsIn response to the recent approval of a disease‐modifying gene therapy for AADC deficiency, this review presents considerations for the selection of patients for treatment.ConclusionSuggested clinical criteria to determine whether a patient is a candidate for gene therapy are: (1) genetically and biochemically confirmed AADC deficiency; (2) lack of achievement of gross motor milestones and/or persistence of clinically significant movement disorders; (3) persistent neurocognitive or systemic symptoms secondary to AADC deficiency despite standard medical therapy; and (4) informed parental/guardian decision and consent to treatment.

The Dopa Decarboxylase (DDC) gene plays an important role in the synthesis of biogenic amines such as dopamine, serotonin, and histamine. Non-synonymous single nucleotide polymorphisms (nsSNPs) in the DDC gene have been linked with various neurodegenerative disorders. In this study, a comprehensive in silico analysis of nsSNPs in the DDC gene was conducted to assess their potential functional consequences and associations with disease outcomes. Using publicly available databases, a complete list of nsSNPs in the DDC gene was obtained. 29 computational tools and algorithms were used to characterise the effects of these nsSNPs on protein structure, function, and stability. In addition, the population-based association studies were performed to investigate possible associations between specific nsSNPs and arthritis. Our research identified four novel DDC gene nsSNPs that have a major impact on the structure and function of proteins. Through molecular dynamics simulations (MDS), we observed changes in the stability of the DDC protein induced by specific nsSNPs. Furthermore, population-based association studies have revealed potential associations between certain DDC nsSNPs and various neurological disorders, including Parkinson’s disease and dementia. The in silico approach used in this study offers insightful information about the functional effects of nsSNPs in the DDC gene. These discoveries provide insight into the cellular processes that underlie cognitive disorders. Furthermore, the detection of disease-associated nsSNPs in the DDC gene may facilitate the development of tailored and targeted therapy approaches.

ObjectivesElectronic health record (EHR) data may facilitate the identification of rare diseases in patients, such as aromatic l-amino acid decarboxylase deficiency (AADCd), an autosomal recessive disease caused by pathogenic variants in the dopa decarboxylase gene. Deficiency of the AADC enzyme results in combined severe reductions in monoamine neurotransmitters: dopamine, serotonin, epinephrine, and norepinephrine. This leads to widespread neurological complications affecting motor, behavioral, and autonomic function. The goal of this study was to use EHR data to identify previously undiagnosed patients who may have AADCd without available training cases for the disease.Materials and MethodsA multiple symptom and related disease annotated dataset was created and used to train individual concept classifiers on annotated sentence data. A multistep algorithm was then used to combine concept predictions into a single patient rank value.ResultsUsing an 8000-patient dataset that the algorithms had not seen before ranking, the top and bottom 200 ranked patients were manually reviewed for clinical indications of performing an AADCd diagnostic screening test. The top-ranked patients were 22.5% positively assessed for diagnostic screening, with 0% for the bottom-ranked patients. This result is statistically significant at P < .0001.ConclusionThis work validates the approach that large-scale rare-disease screening can be accomplished by combining predictions for relevant individual symptoms and related conditions which are much more common and for which training data is easier to create.

Aromatic L-amino acid decarboxylase deficiency (AADCd) is a rare recessive metabolic disorder caused by pathogenic homozygous or compound heterozygous variants in the dopa decarboxylase (DDC) gene. Adeno-associated viral vector-mediated gene transfer of the human DDC gene injected into the putamen is available. The typical presentation is characterized by early-onset hypotonia, severe developmental delay, movement disorders, and dysautonomia. Recently, mild and even atypical phenotypes have been reported, increasing the diagnostic challenge. The aim of this multicentric study is to identify the prevalence of AADCd in a population of patients with phenotypic clusters characterized by neurodevelopmental disorders (developmental delay/intellectual disability, and/or autism) by 3-O-methyldopa (3-OMD) detection in dried blood spots (DBS). It is essential to identify AADCd promptly, especially within non-typical phenotypic clusters, because better results are obtained when therapy is quickly started in mild-moderate phenotypes. Between 2021 and 2023, 390 patients with non-specific phenotypes possibly associated with AADCd were tested; none resulted in a positive result. This result highlights that the population to be investigated for AADCd should have more defined clinical characteristics: association with common signs (hypotonia) and/or pathognomonic symptoms (oculogyric crisis and dysautonomia). It is necessary to continue to screen selected clusters for reaching diagnosis and improving long-term outcomes through treatment initiation. This underscores the role of newborn screening in identifying AADCd.

<h3>Objective:</h3> Investigate the efficacy and safety of eladocagene exuparvovec in patients with aromatic l-amino acid decarboxylase deficiency (AADCd). <h3>Background:</h3> AADCd results from mutations in the dopa decarboxylase gene leading to reduced AADC enzyme activity; it is characterized by motor impairments and inability to attain developmental milestones. Eladocagene exuparvovec is a recombinant adeno-associated viral vector serotype 2 carrying the coding sequence for human AADC. <h3>Design/Methods:</h3> Eladocagene exuparvovec was infused bilaterally in the putamina of 30 children with AADC deficiency in 3 studies (AADC-CU/1601 [n=8], AADC-010 [n=10], and AADC-011 [n=12] in patients aged 18–102 months. Data were extracted on January 4, 2022. Patients receiving a total of 1.8 × 10¹¹ vg (n=21) or 2.4 × 10¹¹ vg (n=9; AADC-011) were followed for up to 120 months and assessed for motor milestone attainment using the Peabody Developmental Motor Scale, 2nd edition (PDMS-2). Specific motor skill items of the PDMS-2 were used to assess motor milestones including head control (partial or full), sitting (supported or independently), standing (with/away from support; up from cross-legged position), and walking (with/without assistance; 10 feet; taped line) Motor milestones and development were measured every 3 months for 1 year following gene therapy, then every 6–12 months for ≤120 months. <h3>Results:</h3> At baseline, no patients mastered head control or more advanced milestones. At year 1 of follow-up, patients were gaining the following skills (n): partial head control (26); full head control (15), sitting unassisted (7), supported standing (2). Progression of development was noted at years 5 and 10. By year 5, more advanced milestones were achieved (n): full head control (24), sitting unassisted (21) assisted walking (5), walking 10 feet (3), or walking up stairs (3). These abilities were maintained for as long as 10 years <h3>Conclusions:</h3> These data indicate eladocagene exuparvovec can provide a durable, positive impact on motor development in patients with AADCd. <b>Disclosure:</b> Mrs. Russell has received personal compensation for serving as an employee of PTC Therapeutics. Mrs. Russell has stock in PTC Therapeutics. Prof. ROUBERTIE has received personal compensation in the range of $500-$4,999 for serving as a Consultant for PTC. Prof. ROUBERTIE has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for PTC. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi Genzyme. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novartis. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Amicus. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Sanofi Genzyme. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Avexis/Norvatis. Yin-Hsiu Chien has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Biogen. The institution of Yin-Hsiu Chien has received research support from Sanofi Genzyme. Ni-Chung Lee has nothing to disclose. Dr. Sierra has received personal compensation for serving as an employee of PTC Therapeutics Inc. Dr. Sierra has stock in PTC Therapeutics Inc. Dr. Turna has received personal compensation for serving as an employee of PTC Therapeutics. Dr. Turna has stock in PTC Therapeutics. Dr. Wang has received personal compensation for serving as an employee of PTC Therapeutics. Dr. Wang has received stock or an ownership interest from PTC Therapeutics, Inc.. The institution of Chun-Hwei Tai has received research support from National Taiwan University Hospital. Paul Wuh-Liang Hwu has received personal compensation in the range of $500-$4,999 for serving as a Consultant for PTC Therapeutics Inc.. Paul Wuh-Liang Hwu has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for PTC therapeutics. The institution of Paul Wuh-Liang Hwu has received research support from PTC therapeutics.

We describe an atypical presentation of a girl with aromatic L-amino acid decarboxylase (AADC) deficiency identified via a genetic testing program for children with epilepsy. At 21 months of age, she presented with poor head control, diffuse hypotonia, poor fixation, developmental delay, and dysphagia. She was lost to follow-up, then presented back at 3 years of age with staring spells and brief episodes of upward eye deviation. The diagnosis of unprovoked epilepsy allowed her to be included in a genetic testing program, which identified two heterozygous variants in the dopa decarboxylase (DCC) gene. Based on the genetic testing, plasma AADC enzyme activity and plasma 3-O-methyldopa results, a diagnosis of AADC deficiency was made when she was 4 years and 2 months of age. This case report shows that AADC deficiency can be the underlying diagnosis in patients with suspected epilepsy.

Pathogenic variants in dopa decarboxylase (DDC), the gene encoding the aromatic l-amino acid decarboxylase (AADC) enzyme, lead to a severe deficiency of neurotransmitters, resulting in neurological, neuromuscular, and behavioral manifestations clinically characterized by developmental delays, oculogyric crises, dystonia, and severe neurologic dysfunction in infancy. Historically, therapy has been aimed at compensating for neurotransmitter abnormalities, but response to pharmacologic therapy varies, and in most cases, the therapy shows little or no benefit. A novel human DDC gene therapy was recently approved in the European Union that targets the underlying genetic cause of the disorder, providing a new treatment option for patients with AADC deficiency. However, the applicability of human DDC gene therapy depends on the ability of laboratories and clinicians to interpret the results of genetic testing accurately enough to diagnose the patient. An accurate interpretation of genetic variants depends in turn on expert-guided curation of locus-specific databases. The purpose of this research was to identify previously uncharacterized DDC variants that are of pathologic significance in AADC deficiency as well as characterize and curate variants of unknown significance (VUSs) to further advance the diagnostic accuracy of genetic testing for this condition. DDC variants were identified using existing databases and the literature. The pathogenicity of the variants was classified using modified American College of Medical Genetics and Genomics/Association for Molecular Pathology/Association for Clinical Genomic Science (ACMG-AMP/ACGS) criteria. To improve the current variant interpretation recommendations, in silico variant interpretation tools were combined with structural 3D modeling of protein variants and applied comparative analysis to predict the impact of the variant on protein function. A total of 422 variants were identified (http://biopku.org/home/pnddb.asp). Variants were identified on nearly all introns and exons of the DDC gene, as well as the 3' and 5' untranslated regions. The largest percentage of the identified variants (48%) were classified as missense variants. The molecular effects of these missense variants were then predicted, and the pathogenicity of each was classified using a number of variant effect predictors. Using ACMG-AMP/ACGS criteria, 7% of variants were classified as pathogenic, 32% as likely pathogenic, 58% as VUSs of varying subclassifications, 1% as likely benign, and 1% as benign. For 101 out of 108 reported genotypes, at least one allele was classified as pathogenic or likely pathogenic. In silico variant pathogenicity interpretation tools, combined with structural 3D modeling of variant proteins and applied comparative analysis, have improved the current DDC variant interpretation recommendations, particularly of VUSs.

This study aimed to investigate the polymorphisms of the dopa decarboxylase (DDC) gene and association analysis with lamb quality and expression quantification of the DDC gene in phenotypically divergent Indonesian sheep. The totals of 189 rams with an average body weight of 24.12 kg at 10 to 12 months were used to identify DDC gene polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Among 189 rams, several rams representing various sheep genotypes were used for an association study between genotypes and phenotypic traits with proc general linear model (GLM) analysis. In addition, the gene expression analysis of the DDC mRNA in the phenotypically divergent sheep population was analyzed using quantitative reverse-transcription PCR. The DDC gene (g. 5377439 G>A) showed polymorphisms that indicated three genotypes: AA, AG, and GG. The DDC gene polymorphism was significantly associated (p≤0.05) with carcass characteristics including carcass percentage, carcass length, hot and cold carcass; physical properties of lamb quality including pH value; retail cut carcass; fatty acid composition such as fat content, pentadecanoic acid (C15:0), tricosylic acid (C23:0), lignoceric acid (C24:0), oleic acid (C18:1n9c), elaidic acid (C18:1n9t), nervonic acid (C24:1), linoleic acid (C18:2n6c), arachidonic acid (C20:4n6), cervonic acid (C22:6n3); and mineral content including potassium (K). The GG genotype of the DDC gene had the best association with lamb quality traits. The DDC gene expression analysis mRNA showed no significant difference (p≥0.05) between lamb quality traits. The DDC gene could be used as a potential candidate gene to improve lamb quality.

Eladocagene exuparvovec (Upstaza™) is a gene therapy developed by PTC Therapeutics for the treatment of human aromatic L-amino acid decarboxylase (AADC) deficiency. Eladocagene exuparvovec comprises an adeno-associated virus vector that delivers the dopa decarboxylase (DDC) gene, the gene for human AADC. Eladocagene exuparvovec was approved in July 2022 in the EU for the treatment of patients aged 18 months and older with a clinical, molecular, and genetically confirmed diagnosis of AADC deficiency with a severe phenotype (i.e. patients who cannot sit, stand or walk). This article summarizes the milestones in the development of eladocagene exuparvovec leading to this first approval for the treatment of patients aged 18 months and older with AADC deficiency.

The 28-spotted potato ladybird, Henosepilachna vigintioctopunctata, is a notorious defoliator of many solanaceous and cucurbitaceous plants. Tyrosine hydroxylase (TH) and dopa decarboxylase (DDC) are responsible for cuticle tanning pathway in insects. We identified HvTH and HvDDC in H. vigintioctopunctata, and found that high levels of them were accumulated just before or right after molting. Injection of dsHvTH or feeding 3-iodo-tyrosine (3-IT) at the third instar larval stage repressed tanning of the larval cuticle, reduced larval feeding, inhibited larval growth, and consequently caused 100% of larval mortality. Knockdown of HvDDC at the third instar larval stage hardly affected the coloration of larval head, and partially inhibited pigmentation of larval bodies and around 80% of the HvDDC RNAi larvae developed into albino pupae and adults. Moreover, depletion of HvTH or HvDDC at the fourth instar larval stage resulted in albino pupae and adults. The HvTH or HvDDC hypomorph adults fully or partially failed to remove the larval/pupal exuviae, possessed pale and abnormal wings, and poorly tanned heads and bodies, and eventually, struggled for several days without feeding on leaves before death. These results show that TH and DDC play key roles in larval and adult cuticle tanning and development in H. vigintioctopunctata. Also, these findings suggest that dopa- and dopamine-originated pigments are essential for larval and adult feeding behavior and the molting process during emergence. © 2022 Society of Chemical Industry.

Dopamine is the precursor of a variety of natural antioxidant compounds. In the body, dopamine acts as a neurotransmitter that regulates a variety of physiological functions of the central nervous system. Thus, dopamine is used for the clinical treatment of various types of shock. Dopamine could be produced by engineered microbes, but with low efficiency. In this study, DOPA decarboxylase gene from Sus scrofa (Ssddc) was cloned into plasmids with different copy numbers, and transformed into a previously developed L-DOPA producing strain Escherichia coli T004. The resulted strain was capable of producing dopamine from glucose directly. To further improve the production of dopamine, a sequence-based homology alignment mining (SHAM) strategy was applied to screen more efficient DOPA decarboxylases, and five DOPA decarboxylase genes were selected from 100 candidates. In shake-flask fermentation, the DOPA decarboxylase gene from Homo sapiens (Hsddc) showed the highest dopamine production (3.33 g/L), while the DOPA decarboxylase gene from Drosophila Melanogaster (Dmddc) showed the least residual L-DOPA concentration (0.02 g/L). In 5 L fed-batch fermentations, production of dopamine by the two engineered strains reached 13.3 g/L and 16.2 g/L, respectively. The residual concentrations of L-DOPA were 0.45 g/L and 0.23 g/L, respectively. Finally, the Ssddc and Dmddc genes were integrated into the genome of E. coli T004 to obtain genetically stable dopamine-producing strains. In 5 L fed-batch fermentation, 17.7 g/L of dopamine was produced, which records the highest titer reported to date.

Dopa decarboxylase (DDC) synthesizes serotonin in the developing mouse heart where it is encoded by Ddc_exon1a, a tissue-specific paternally expressed imprinted gene. Ddc_exon1a shares an imprinting control region (ICR) with the imprinted, maternally expressed (outside of the central nervous system) Grb10 gene on mouse chromosome 11, but little else is known about the tissue-specific imprinted expression of Ddc_exon1a. Fluorescent immunostaining localizes DDC to the developing myocardium in the pre-natal mouse heart, in a region susceptible to abnormal development and implicated in congenital heart defects in human. Ddc_exon1a and Grb10 are not co-expressed in heart nor in brain where Grb10 is also paternally expressed, despite sharing an ICR, indicating they are mechanistically linked by their shared ICR but not by Grb10 gene expression. Evidence from a Ddc_exon1a gene knockout mouse model suggests that it mediates the growth of the developing myocardium and a thinning of the myocardium is observed in a small number of mutant mice examined, with changes in gene expression detected by microarray analysis. Comparative studies in the human developing heart reveal a paternal expression bias with polymorphic imprinting patterns between individual human hearts at DDC_EXON1a, a finding consistent with other imprinted genes in human.