Chromosome 11, Partial Monosomy 11q

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Chromosome 11, Partial Monosomy 11q is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Partial monosomy 11q, also known as Jacobsen syndrome, is a rare chromosomal disorder in which a portion of chromosome 11 is missing or deleted 11q monosomy. The range and severity of symptoms varies, depending in part on the exact location and size of the missing material. Symptoms commonly associated with partial monosomy 11q include abnormally slow growth before and after birth (prenatal and postnatal growth retardation), and/or moderate to severe delays in the acquisition of skills requiring the coordination of mental and muscular activity (psychomotor retardation). In rare cases, individuals may have normal/borderline intelligence while in most cases children have mild to severe intellectual disability. Characteristic physical abnormalities may include malformations of the head and face (craniofacial), abnormalities of the eyes, hands, feet, bleeding due to platelet abnormalities, and/or defects of the heart that are present at birth (congenital), and immunological defects. The exact cause of partial monosomy 11q is not fully understood.

Supporting Organizations

11q Research and Resource Group

5155 Shotwell Street
Woodstock, GA 30188
Tel: (404)428-8440

American Speech-Language-Hearing Association

2200 Research Boulevard
Rockville, MD 20850-3289
United States
Tel: (301)296-5700
Fax: (301)296-8580
Tel: (800)638-8255

Children's Craniofacial Association

13140 Coit Road
Suite 517
Dallas, TX 75240
Tel: (214)570-9099
Fax: (214)570-8811
Tel: (800)535-3643

Chromosome Disorder Outreach, Inc.

P.O. Box 724
Boca Raton, FL 33429-0724
Tel: (561)395-4252
Fax: (561)395-4252

Craniofacial Foundation of America

975 East Third Street
Chattanooga, TN 37403
Tel: (423)778-9176
Fax: (423)778-8172
Tel: (800)418-3223

European Chromosome 11q Network

Sparkasse Pforzheim D
Wiernsheim, 85421
Tel: 31317423345
Fax: 31317426980

FACES: The National Craniofacial Association

PO Box 11082
Chattanooga, TN 37401
Tel: (423)266-1632
Fax: (423)267-3124
Tel: (800)332-2373

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

March of Dimes

1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Email: or
Website: and

NIH/National Heart, Lung and Blood Institute

P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

NIH/National Institute on Deafness and Other Communication Disorders

31 Center Drive, MSC 2320
Communication Avenue
Bethesda, MD 20892-3456
Tel: (301)402-0900
Fax: (301)907-8830
Tel: (800)241-1044

UNIQUE - Rare Chromosome Disorder Support Group

G1 The Stables
Station Road West
Oxted, RH8 9EE
United Kingdom
Tel: 0044 (0)1883 723356

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  8/3/2015
Copyright  2015 National Organization for Rare Disorders, Inc.