Ellis – van Creveld syndrome is an autosomal recessive disorder manifest by short-limb dwarfism, thoracic dystrophy, postaxial polydactyly, dysplastic nails and teeth, and an approximately 60% incidence of congenital malformations of the heart. Despite patients with Ellis – van Creveld syndrome being regarded as having a high surgical risk, few data are available regarding their outcomes following surgery for congenital malformations of the heart in the current era.
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Published Papers
The primary goal of our research will always be to find effective and affordable treatments for patients. One of the central focus areas of our mission is sharing our methods and discoveries with the broader scientific community.
In the over 35 years since the Clinic's founding, our staff have published more than 130 peer-reviewed research papers, fueled by close collaboration between our clinical and laboratory teams and effective relationships with academic, scientific, and clinical partners.
Authors: Xin B, Jones S, Puffenberger EG, Hinze C, Bright A, Tan H, Zhou A, Wu G, Vargus-Adams J, Agamanolis D, Wang H
We describe an autosomal recessive condition characterized with cerebral vasculopathy and early onset of stroke in 14 individuals in Old Order Amish. The phenotype of the condition was highly heterogeneous, ranging from severe developmental disability to normal schooling. Cerebral vasculopathy was a major hallmark of the condition with a common theme of multifocal stenoses and aneurysms in large arteries, accompanied by chronic ischemic changes, moyamoya morphology, and evidence of prior acute infarction and hemorrhage. Early signs of the disease included mild intrauterine growth restriction, infantile hypotonia, and irritability, followed by failure to thrive and short stature. Acrocyanosis, Raynaud’s phenomenon, chilblain lesions, low-pitch hoarse voice, glaucoma, migraine headache, and arthritis were frequently observed. The early onset or recurrence of strokes secondary to cerebral vasculopathy seems to always be associated with poor outcomes. The elevated erythrocyte sedimentation rate (ESR), IgG, neopterin, and TNF-α found in these patients suggested an immune disorder. Through genomewide homozygosity mapping, we localized the disease gene to chromosome (Chr) 20q11.22-q12. Candidate gene sequencing identified a homozygous mutation, c.1411–2A > G, in the SAMHD1 gene, being associated with this condition. The mutation appeared at the splice-acceptor site of intron 12, resulted in the skipping of exon 13, and gave rise to an aberrant protein with in-frame deletion of 31 amino acids. Immunoblotting analysis showed lack of mutant SAMHD1 protein expression in affected cell lines. The function of SAMHD1 remains unclear, but the inflammatory vasculopathies of the brain found in the patients with SAMHD1 mutation indicate its important roles in immunoregulation and cerebral vascular hemeostasis.
Authors: Shellmer DA, DeVito Dabbs A, Dew MA, Noll RB, Feldman H, Strauss KA, Morton DH, Vockley J, Mazariegos GV
MSUD is a complex metabolic disorder that has been associated with central nervous system damage, developmental delays, and neurocognitive deficits. Although liver transplantation provides a metabolic cure for MSUD, changes in cognitive and adaptive functioning following transplantation have not been investigated. In this report we present data from 14 patients who completed cognitive and adaptive functioning testing pre- and one year and/or three years postliver transplantation. Findings show either no significant change or improvement in IQ scores preto post-liver transplantation. Greater variability was observed in adaptive functioning scores, but the majority of patients evidenced either no significant change or improvement in adaptive scores. In general, findings may indicate that liver transplantation curtails additional central nervous system damage and neurocognitive decline providing an opportunity for stabilization or improvement in functioning.
Authors: Lancaster E, Huijbers MG, Bar V, Boronat A, Wong A, Martinez-Hernandez E, Wilson C, Jacobs D, Lai M, Walker RW, Graus F, Bataller L, Illa I, Markx S, Strauss KA, Peles E, Scherer SS, Dalmau J
To report clinical and immunological investigations of contactin-associated proteinlike 2 (Caspr2), an autoantigen of encephalitis and peripheral nerve hyperexcitability (PNH) previously attributed to voltage-gated potassium channels (VGKC).
Authors: Rajadhyaksha AM, Elemento O, Puffenberger EG, Schierberl KC, Xiang JZ, Putorti ML, Berciano J, Poulin C, Brais B, Michaelides M, Weleber RG, Higgins JJ
The study of inherited retinal diseases has advanced our knowledge of the cellular and molecular mechanisms involved in sensory neural signaling. Dysfunction of two specific sensory modalities, vision and proprioception, characterizes the phenotype of the rare, autosomal-recessive disorder posterior column ataxia and retinitis pigmentosa (PCARP). Using targeted DNA capture and high-throughput sequencing, we analyzed the entire 4.2 Mb candidate sequence on chromosome 1q32 to find the gene mutated in PCARP in a single family. Employing comprehensive bioinformatic analysis and filtering, we identified a single-nucleotide coding variant in the feline leukemia virus subgroup C cellular receptor 1 (FLVCR1), a gene encoding a heme-transporter protein. Sanger sequencing confirmed the FLVCR1 mutation in this family and identified different homozygous missense mutations located within the protein’s transmembrane channel segment in two other unrelated families with PCARP. To determine whether the selective pathologic features of PCARP correlated with FLVCR1 expression, we examined wild-type mouse Flvcr1 mRNA levels in the posterior column of the spinal cord and the retina via quantitative real-time reverse-transcriptase PCR. The Flvcr1 mRNA levels were most abundant in the retina, followed by the posterior column of the spinal cord and other brain regions. These results suggest that aberrant FLVCR1 causes a selective degeneration of a subpopulation of neurons in the retina and the posterior columns of the spinal cord via dysregulation of heme or iron homeostasis. This finding broadens the molecular basis of sensory neural signaling to include common mechanisms that involve proprioception and vision.
Authors: Innes AM, Boycott KM, Puffenberger EG, Redl D, MacDonald IM, Chudley AE, Beaulieu C, Perrier R, Gillan T, Wade A, Parboosingh JS
Bardet-Biedl syndrome (BBS) is a multisystem genetically heterogeneous disorder, the clinical features of which are largely the consequence of ciliary dysfunction. BBS is typically inherited in an autosomal recessive fashion, and mutations in at least 14 genes have been identified. Here, we report the identification of a founder mutation in the BBS2 gene as the cause for the increased incidence of this developmental disorder in the Hutterite population. To ascertain the Hutterite BBS locus, we performed a genome-wide single nucleotide polymorphism (SNP) analysis on a single patient and his three unaffected siblings from a Hutterite family. The analysis identified two large SNP blocks that were homozygous in the patient but not in his unaffected siblings, one of these regions contained the BBS2 gene. Sequence analysis and subsequent RNA studies identified and confirmed a novel splice site mutation, c.472-2A>G, in BBS2. This mutation was also found in homozygous form in three subsequently studied Hutterite BBS patients from two different leuts, confirming that this is a founder mutation in the Hutterite population. Further studies are required to determine the frequency of this mutation and its role, if any, in the expression of other ciliopathies in this population.
Authors: Boycott KM, Beaulieu C, Puffenberger EG, McLeod DR, Parboosingh JS, Innes AM
The Hutterites are a genetically isolated Anabaptist group living on the North American prairies; their population numbers over 40,000, the majority of whom are descendants of 89 founders. An autosomal recessive developmental disorder was identified in four patients from two consanguineous Hutterite families. To our knowledge the clinical presentation is unique and undescribed. The patients have distinctive facial features, congenital malformations of the heart and genitourinary system, head circumference at the 2nd centile and developmental delay. The facial features include tall forehead with high anterior hairline, deep-set eyes with short, upslanted palpebral fissures, long nose with low-hanging columella, and thick vermilion of the upper and lower lip. Karyotype and baseline metabolic studies were normal. An identity-by-descent mapping approach was used to localize the gene for this disorder. The patients were genotyped using Affymetrix GeneChip Human Mapping 10 K (Xba 2.0) and 50 K (Xba 240) Arrays which identified a single 5.5 Mb homozygous region at chromosome 16p13.3. To confirm and refine the boundaries of this region, microsatellite markers were used to genotype the patients, their parents, and the available unaffected siblings. The disease locus was refined to a region of 5.1 Mb containing 173 known or predicted genes. No other recessive disorders with similar clinical features are currently mapped to this region. The coding regions of over fifteen genes, prioritized by microarray expression analysis and information available in public databases, have been sequenced, but no potential pathogenic mutations have been identified. The identification of the gene for this syndrome will provide new insights into development and learning.
Authors: Strauss KA, Wardley B, Robinson D, Hendrickson C, Rider NL, Puffenberger EG, Shellmer D, Moser AB, Morton DH
Branched-chain ketoacid dehydrogenase deficiency results in complex and volatile metabolic derangements that threaten brain development. Treatment for classical maple syrup urine disease (MSUD) should address this underlying physiology while also protecting children from nutrient deficiencies. Based on a 20-year experience managing 79 patients, we designed a study formula to (1) optimize transport of seven amino acids (Tyr, Trp, His, Met, Thr, Gln, Phe) that compete with branched-chain amino acids (BCAAs) for entry into the brain via a common transporter (LAT1), (2) compensate for episodic depletions of glutamine, glutamate, and alanine caused by reverse transamination, and (3) correct deficiencies of omega-3 essential fatty acids, zinc, and selenium widespread among MSUD patients. The formula was enriched with LAT1 amino acid substrates, glutamine, alanine, zinc, selenium, and alpha-linolenic acid (18:3n-3). Fifteen Old Order Mennonite children were started on study formula between birth and 34 months of age and seen at least monthly in the office. Amino acid levels were checked once weekly and more often during illnesses. All children grew and developed normally over a period of 14-33 months. Energy demand, leucine tolerance, and protein accretion were tightly linked during periods of normal growth. Rapid shifts to net protein degradation occurred during illnesses. At baseline, most LAT1 substrates varied inversely with plasma leucine, and their calculated rates of brain uptake were 20-68% below normal. Treatment with study formula increased plasma concentrations of LAT1 substrates and normalized their calculated uptakes into the nervous system. Red cell membrane omega-3 polyunsaturated fatty acids and serum zinc and selenium levels increased on study formula. However, selenium and docosahexaenoic acid (22:6n-3) levels remained below normal. During the study period, hospitalizations decreased from 0.35 to 0.14 per patient per year. There were 28 hospitalizations managed with MSUD hyperalimentation solution; 86% were precipitated by common infections, especially vomiting and gastroenteritis. The large majority of catabolic illnesses were managed successfully at home using ‘sick-day’ formula and frequent amino acid monitoring. We conclude that the study formula is safe and effective for the treatment of classical MSUD. In principle, dietary enrichment protects the brain against deficiency of amino acids used for protein accretion, neurotransmitter synthesis, and methyl group transfer. Although the pathophysiology of MSUD can be addressed through rational formula design, this does not replace the need for vigilant clinical monitoring, frequent measurement of the complete amino acid profile, and ongoing dietary adjustments that match nutritional intake to the metabolic demands of growth and illness.
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Our clinic serves as a trusted medical practice for children and adults facing rare genetic disorders. Our dedicated team works every day to prevent and treat genetic illnesses. Our facility is in the heart of the Amish and Mennonite communities in Lancaster County. Inside is filled with cutting-edge gene sequencing tools that allow us to deliver highly personalized care—a precise treatment option for the right patient at the right time.