OOA (Old Order Amish)

Inheritance: autosomal recessive
Genes: C7ORF11

Hair-brain syndrome
BIDS syndrome
Nonphotosensitive trichothiodystrophy

Brittle hair
Intellectual impairment
Short stature
Decreased fertility

Brittle Hair Syndrome, Amish Type

Clinical Characteristics

General description (for patients): 

One of the earliest descriptions of this disease was in 1974 by Jackson, et al, who studied a large Amish kindred in Northern Indiana traced to immigrants from Switzerland in 1736. It occurs in Holmes County, OH, also.  The characteristic manifestations of this disease include brittle hair, short stature, mild intellectual impairment, and decreased fertility.  Hair is often fine and thin in females who do not cut their hair but often thicker and more coarse in males who get regular haircuts.  Fingernails may be normal or abnormally brittle.

Medical description: 

The outstanding feature of this syndrome is that of sparse, short and brittle hair.  The hair of the head, beard, eyebrows, eyelashes, axillary and pubic areas may all be abnormal.  Upon light or electron microscopy examination the hair shaft lacks normal scales, and has an irregular and grooved surface that appears twisted.  Sulfur and cysteine content of the hair is reduced.  Skin and teeth on the other hand appear normal, but nails may be absent or small. The affected individual is often described as ‘slow ‘ by their families, with below average intelligence as denoted by psychometric testing.  School performance may be subpar.  Despite their learning impairments individuals function well within their rural Amish communities.  Stature is approximately one standard deviation below the mean for age and sex.  Affected individuals have relatively few offspring for a community known for its large families.  For example, in the Indiana isolate, an average of ten live children was born to all women with completed families. In contrast an average of only 0.81 children were born to affected married individuals, compared to 2.85 children to unaffected married siblings and 6.41 for their parents. It is thought that the relative infertility in affected male individuals is due to a decrease in disulphide bonds in sperm.  Numerous cases have been found in Holmes County as well.


Sequence mutations in the C7ORF11 (TTDN1) gene located on chromosome 7 (7p14) have been identified in Amish patients.  This is an autosomal recessive disease.


There is no treatment known to prevent or delay the symptoms.


There is no evidence of reduced lifespan.

Ancillary treatments and support: 

No special treatment is required.

Specialists and specialty centers: 



Jackson, C.E., Weiss, L., and Watson, J.H.L.: ‘Brittle’ hair with short stature, intellectual impairment and decreased fertility: an autosomal recessive syndrome in an Amish kindred. Pediatrics 54: 201-208, 1974.  PubMed ID: 4847854

Seboun, E., Lemanique, A., and Jackson, C.E.: Amish brittle hair syndrome gene maps to 7p14.1. Am. J. Med. Genet.  134A: 290-294, 2005. PubMed ID: 15723315

Nakabayashi, K., Amann, D., Ren, Y.; Saarialho-Kere, U., Avidan, N., Gentles, S., MacDonald, J. R., Puffenberger, E. G., Christiano, A. M., Martinez-Mir, A., Salas-Alanis, J. C., Rizzo, R., Vamos, E., Raams, A., Les, C., Seboun, E., Jaspers, N. G. J., Beckmann, J. S., Jackson, C. E., Scherer, S. W.:  Identification of C7orf11 (TTDN1) gene mutations and genetic heterogeneity in nonphotosensitive trichothiodystrophy.  Am. J. Hum. Genet. 76: 510-516, 2005.  PubMed ID: 15645389


No available resource at this time