Clinical Services

Our clinical staff is dedicated to providing primary pediatric care to children with complex genetic disorders, focusing on the uninsured rural Amish and Mennonite communities of Southeastern Pennsylvania. We currently care for over 2,500 patients with 150 known disorders including maple syrup urine disease (MSUD), glutaric acidemia (GA-1) and propionic acidemia. Office visits are conducted in our timber frame building in Strasburg, PA. Acute crises are managed at Lancaster General Hospital (LGH) where our physicians attend all inpatient treatment. We also offer on-site, limited subspecialty services for our patients through partnerships with LGH and Nemours/ Alfred I. DuPont Hospital for Children. The Clinic for Special Children is designed as a “medical home” for children with genetic disorders; a place where children can receive needed care in an accessible, comfortable, informed environment.

Laboratory Services

The CLIA-certified biochemical and molecular genetics laboratory at the Clinic for Special Children provides various assays for its patients. These include, but are not limited to, amino acid analysis, real-time molecular diagnostic testing, molecular cytogenetic analysis, and exploratory gene mapping. Since CSC is a small, non-profit organization, substantially supported by the unique populations we serve, the laboratory cannot accept outside samples and reserves the right to refuse samples sent without prior authorization. The molecular genetic testing we offer is limited to pathogenic mutations found in the Old Order Amish and Mennonite populations of Southeastern Pennsylvania. Biochemical assays we offer for our patients are readily available at other testing laboratories throughout the country. Information regarding laboratory services is provided here for the benefit of our patients and their local healthcare providers.

Specimen Requirements

Molecular genetic analysis

2-3 ml whole blood in EDTA (lavender top tube.) Ship whole blood at room temperature by overnight express (FedEx or UPS.) Do not freeze whole blood. A completed and signed consent and requisition form must accompany the sample.

Amino acid analysis


  1. >1ml serum or plasma, frozen and shipped on dry ice or
  2. Guthrie card (filter paper) with four, >1 cm diameter blood spots

Shipped by overnight express (FedEx or UPS.) A completed and signed consent and requisition form must accompany the sample.

Consent and Requisition forms

All requests for molecular genetic testing (carrier tests, etc.) must be accompanied by a completed and signed consent and requisition form.


Please read the specimen requirements above and ship samples by overnight express (FedEx or UPS) for delivery Monday-Friday to the following address:

Clinic for Special Children
Attn: Dr. Erik G. Puffenberger, Lab Director
535 Bunker Hill Road
Strasburg, PA 17579


The Clinic for Special Children does not bill insurance companies. Since we are a non-profit organization, laboratory services are offered at a reduced cost compared to other laboratories. If payment is not received with the sample, or prior arrangements have not been made with our billing staff, the test may be delayed or refused. Current charges are as follows:

  • Targeted mutation detection (carrier or diagnostic testing for a known, specific mutation):
    • Individual samples:
      First mutation: $50 per sample
      Subsequent mutations: $35 per sample per mutation
    • Couples:
      First mutation: $85 per couple (must be same mutation for each sample)
      Subsequent mutations: $70 per couple
  • Amino acid analysis: $75 per sample ($150 for new patients)

CLIA ID: 39D0662473, PA Lab ID: 021547, EIN: 23-2555373

Diseases & Mutations

  • Sitosterolemia
    ABCG8 c.1720G>A — Amish
  • Medium-chain acyl-CoA dehydrogenase deficiency
    ACADM c.985A>G — Mennonite
    ACADM IVS4-30A>G — Mennonite
  • Adenosine deaminase deficiency
    ADA c.646G>A — Amish
  • Weil-Marchesani syndrome
    ADAMTS10 17,346 bp deletion — Amish
  • Vitamin B12 deficiency
    AMN 43 bp deletion — Mennonite
  • Torkelson syndrome
    APOA4 c.552_749dup — Mennonite
  • Familial hypercholesterolemia
    APOB c.10580G>A — Amish
  • Byler disease
    ATP8B1 c.923G>T — Amish
  • Familial hypercholanemia
    BAAT c.226A>G — Amish
  • Bardet-Biedl syndrome
    BBS1 c.1169T>G — Amish
  • Maple syrup urine disease
    BCKDHA c.1312T>A — Mennonite
  • Lethal neonatal rigidity and multifocal epilepsy
    BRAT1 c.638_639insA — Amish
  • Biotinidase deficiency
    BTD c.1330G>C — Amish
    BTD c.1368A>C — Amish
    BTD c.1459T>C — Mennonite
  • Glutaric aciduria, type 3
    C7orf10 c.895C>T — Amish
  • Timothy syndrome
    CACNA1C c.1216G>A — Amish
  • Limb-girdle muscular dystrophy, type 2A
    CAPN3 c.2306G>A — Amish
  • Properdin deficiency
    CFP c.379T>G — Mennonite
  • Multiple pterygium syndrome, Escobar variant
    CHRNG c.459_460insA — Amish
  • Spondyloepiphyseal dysplasia and humerospinal dysostosis
    CHST3 c.1298C>T — Amish
  • Bartter syndrome
    CLCNKB 22,508 bp deletion — Amish
  • Achromotopsia
    CNGA3 c.1126G>A — Mennonite
  • Cortical dysplasia and focal epilepsy
    CNTNAP2 c.3709delG — Amish
  • Knobloch syndrome
    COL18A1 c.4054_4055delCT — Amish
  • Osteogenesis imperfecta
    COL1A2 c.2098G>T — Amish
  • Non-syndromic mental retardation
    CRADD c.382G>C
  • Chronic granulomatous disease
    CYBB c.1222G>A — Amish
    CYBB c.1335C>A — Amish
  • 11-beta-hydroxylase deficiency
    CYP11B1 c.1343G>A — Amish
  • Aldosterone deficiency
    CYP11B2 5 bp deletion — Amish
  • Congenital adrenal hyperplasia due to 21-hydroxylase deficiency
    CYP21A2 c.518T>A — Amish
  • Primary ciliary dyskinesia
    DNAH5 c.4348C>T — Amish
  • Dilated cardiomyopathy with arrhythmia
    DSP c.699G>A — Amish
  • Hirschsprung disease
    EDNRB c.828G>T — Mennonite
  • Cockayne syndrome
    ERCC6 IVS14+1G>T — Amish
  • Ellis-van Creveld syndrome
    EVC IVS13+5G>T — Amish
  • Factor 11 deficiency
    F11 c.1327C>T — Mennonite
  • Factor 5 deficiency
    F5 c.1601G>A — Amish and Mennonite
  • Apert syndrome
    FGFR2 c.758C>G — Amish
  • Thanatophoric dysplasia
    FGFR3 c.742C>T — Amish and Mennonite
  • Posterior column ataxia and retinitis pigmentosa
    FLVCR1 c.361A>G — Mennonite
  • Fragile X syndrome
    FMR1 (CGG)n expansion — Mennonite
  • Galactosemia
    GALT c.563A>G — Amish
    GALT c.940A>G — Amish
  • Glutaric aciduria, type 1
    GCDH c.1262C>T — Amish
  • Non-syndromic deafness
    GJB2 c.35delG — Amish and Mennonite
  • Hypomyelinating leukodystrophy
    GJC2 c.203A>G — Amish
  • GM1-gangliosidosis
    GLB1 c.902C>T — Amish
  • Non-ketotic hyperglycinemia
    GLDC c.128delA — Amish
    GLDC c.2186delC — Amish
  • Usher-like syndrome
    HARS c.1361A>C — Amish
  • Non-syndromic intellectual disability, autism, and gait disturbance
    HERC2 c.1781C>T
  • Hereditary hemochromatosis
    HFE c.187C>G — Amish
    HFE c.845G>A — Amish
  • Tyrosinemia, type 3
    HPD c.1005C>G — Mennonite
    HPD c.479A>G — Mennonite
    HPD c.85G>A — Mennonite
  • 3-β-OH-steroid dehydrogenase deficiency
    HSD3B2 c.35G>A — Amish
  • Severe combined immune deficiency
    IL7R c.2T>G — Mennonite
  • ITCH deficiency
    ITCH c.394_395insA — Amish
  • Cerebral cavernous malformations
    KRIT1 c.47G>C — Mennonite
  • Pierson syndrome
    LAMB2 c.440A>G — Mennonite
  • Dilated cardiomyopathy with AV block
    LMNA c.568C>T — Amish
  • Osteoporosis-pseudoglioma syndrome
    LRP5 c.1225A>G — Mennonite
    LRP5 c.1275G>A — Mennonite
  • 3-methylcrotonylglycinuria
    MCCC2 c.295G>C — Amish
    MCCC2 c.518insT — Mennonite
    MCCC2 c.687A>C — Mennonite
  • McKusick-Kauffman syndrome
    MKKS [c.250C>T + c.724G>T] — Amish
  • Methylmalonic aciduria and homocystinuria, cblC type
    MMACHC c.271insA — Amish
  • Homocystinuria
    MTHFR c.1129C>T — Amish
  • Spastic ataxia
    MTPAP c.1432A>G — Amish
  • Mevalonate kinase deficiency
    MVK c.1174G>A — Mennonite
    MVK c.803T>C — Mennonite
  • Gray platelet syndrome
    NBEAL2 c.881C>G
  • Congenital nephrotic syndrome
    NPHS1 c.1481delC — Mennonite
    NPHS1 c.3250delG — Mennonite
  • Nephrotic syndrome
    NPHS2 c.413G>A — Amish
  • Congenital insensitivity to pain with anhidrosis
    NTRK1 IVS12+1G>A — Mennonite
  • Ornithine transcarbamylase deficiency
    OTC c.422G>A — Amish
  • Phenylketonuria
    PAH c.283_285delATC — Amish
    PAH c.782G>A — Amish
    PAH c.782G>A — Mennonite
    PAH IVS10-11G>A — Mennonite
    PAH IVS12+1G>A — Mennonite
  • Propionic acidemia
    PCCB c.1606A>G — Amish and Mennonite
  • Prolidase deficiency
    PEPD c.793C>T — Amish
  • Pyruvate kinase deficiency
    PKLR c.1436G>A — Amish
  • Glycogen storage disease, type 6
    PYGL IVS13+1G>A — Mennonite
  • Severe combined immune deficiency
    RAG1 c.2974A>G — Amish
  • Cartilage-hair hypoplasia
    RMRP c.70A>G — Amish
  • Alpha-1 antitrypsin deficiency
    SERPINA1 c.1096G>A — Amish and Mennonite
  • Limb-girdle muscular dystrophy
    SGCB c.271C>T — Amish
    SGCB c.452C>G — Amish
  • Gittelman syndrome
    SLC12A3 8,627 bp deletion — Amish
    SLC12A3 c.1924C>G — Amish
  • Salla disease
    SLC17A5 c.115C>T — Mennonite
  • Amish microcephaly
    SLC25A19 c.530G>C — Amish
  • Hypertrophic cardiomyopathy
    SLC25A4 c.523delC — Mennonite
  • Cystinuria
    SLC3A1 c.1354C>T — Mennonite
    SLC3A1 IVS6+2T>C — Mennonite
  • Infantile parkinsonism-dystonia syndrome
    SLC6A3 [c.1408T>A + c.1409A>G] — Amish
    SLC6A3 IVS9+1G>A — Mennonite
  • Cystinuria
    SLC7A9 c.1166C>T — Mennonite
    SLC7A9 c.201C>T — Mennonite
  • Spinal muscular atrophy
    SMN1 exon 7 deletion — Mennonite
  • Symptomatic epilepsy and skull dysplasia
    SNIP1 c.1097A>G
  • Troyer syndrome
    SPG20 c.1110delA — Amish
  • GM3 synthase deficiency
    ST3GAL5 c.694C>T — Amish
  • STRADA deficiency
    STRADA 7 kb deletion — Mennonite
  • Aplastic anemia and pulmonary fibrosis
    TERT c.1710G>C — Mennonite
  • Tyrosine hydroxylase deficiency
    TH c.698G>A — Mennonite
  • Familial hypercholanemia
    TJP2 c.143T>C — Amish
  • TMCO1 defect syndrome
    TMCO1 c.139_140delAG — Amish
  • Familial periodic fever
    TNFRSF1A c.362G>A — Mennonite
  • Nemaline rod myopathy
    TNNT1 c.505G>T — Amish
  • Torsion dystonia
    TOR1A c.907_909delGAG — Mennonite
  • Sudden infant death with dysgenesis of the testes
    TSPYL1 c.457_458insG — Amish
  • Microcephaly with chorioretinopathy
    TUBGCP6 c.5458T>G — Mennonite
  • Crigler-Najjar syndrome
    UGT1A1 c.222C>A — Amish and Mennonite
  • Restrictive dermopathy
    ZMPSTE24 c.54_55insT — Mennonite
  • Hereditary spherocytosis/elliptocytosis
    SPTA1 c.6154delG – Mennonite