History
The patient history may reveal clues to the diagnosis, such as the following:
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Course of pregnancy and delivery: Most children with Nijmegen breakage syndrome are born at term, in vertical presentation.
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Early somatic development: Birth weight, length, and head circumference are usually significantly lower in comparison with sex-matched controls; a slow growth rate and poor weight gain is observed in infancy and early childhood.
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Psychomotor development: Usually, no gross delay of milestones is observed during the first year of life; toddlers and preschool children are frequently hyperactive; speech delay is common.
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Mild complications after vaccinations (ie, against polio or measles) or in the course of childhood infectious diseases (eg, varicella) are reported in some patients.
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Recurring infections: These are mainly of the respiratory tract, urinary tract, and gastrointestinal system, and they become a problem in approximately two thirds of patients.
The following information from the family history is also particularly important:
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Occurrence of microcephaly or hydrocephaly in patient's siblings
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Death of patient's siblings due to malignancy or severe infection
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Malignancies among other family members
Physical Examination
Microcephaly
Microcephaly (ie, head circumference below the third percentile) is the most striking and consistent symptom of Nijmegen breakage syndrome. In the great majority of children, it is observed at birth; in individuals who were born with a head circumference within the reference range, progressive and severe microcephaly develops during the first months of life. However, despite severe and progressive microcephaly, neuromotor development is not disturbed; epileptic seizures are not characteristic of the disease.
Among the 77 patients of Polish descent whom Chrzanowska observed, the deficiency of occipitofrontal circumference ranged from -4.4 to -9 standard deviation, but the proportions among the diminished head measurements (length and breadth) were retained.
Craniofacial characteristics
A sloping forehead and receding mandible, a prominent midface with a relatively long nose, upward slanting of the palpebral fissures (in most), and relatively large and dysplastic ears (in some) characterize the facial appearance in Nijmegen breakage syndrome, which is similar among all patients. The craniofacial characteristics of Nijmegen breakage syndrome become more obvious with patient age, probably because of progressive microcephaly. Note the images below.

Growth retardation
Children with Nijmegen breakage syndrome, in spite of being born at term, are characterized by a significantly lower birth weight and head circumference in comparison with sex-matched controls, as well as lower birth length and chest circumference.
The range of birth weight of Polish neonates was 1900-3600 g for females and 2170-3950 g for males.
After approximately a 2-year period of distinct postnatal growth retardation, a slight improvement in the growth rate (including those of body height and weight but not head circumference) is usually observed (Polish data).
Most patients' growth is around the third percentile for height and weight; in some teenage patients, growth is between the 10th and 25th percentiles for height and weight. Young adult individuals with Nijmegen breakage syndrome can reach a height of approximately 165 cm (ie, approximately 50th percentile for females and less than third percentile for males; Polish data).
Sexual maturation
Results of long-term follow-up in a large group of Polish patients drew attention to the poor development of secondary sex characteristics (ie, lack of development of genital organs and breasts, primary amenorrhea) in female patients with Nijmegen breakage syndrome who reached pubertal age. [54]
Endocrinologic evaluation indicates ovarian failure (see Lab Studies). Affected female patients fail to reach sexual maturity because of hypergonadotropic hypogonadism. [54, 55]
Immune deficiency and recurring infections
Because of defective humoral and cellular immunity, Nijmegen breakage syndrome patients are prone to developing infections. A considerable variability in immune deficiency is observed among different patients. [56]
The most common infections are respiratory tract infections (pneumonia, bronchitis) and sinusitis. Recurrent bronchopneumonia may result in bronchiectasis. Urinary and/or gastrointestinal tract infections and otitis media are also relatively common. Opportunistic infections are rare, as they are in patients with A-T.
Immunodeficiency in Nijmegen breakage syndrome is caused by reduced numbers of peripheral B and T lymphocytes, which can be explained as a precursor B-cell and, probably, also T-cell differentiation problem, due to a dysfunction of a truncated nibrin molecule. [57] A defect in humoral immunity in Nijmegen breakage syndrome patients is caused by reduced numbers of peripheral B lymphocytes and, simultaneously, by failure of their maturation, which results in an ineffective class-switch recombination. [58]
Malignancies
Malignancy is the most common cause of death in patients with Nijmegen breakage syndrome.
The prevalence of lymphoid malignancies in individuals with Nijmegen breakage syndrome is unprecedentedly high compared with healthy individuals and persons with other cancer-predisposing diseases such as A-T, Bloom syndrome, and FA. To date, 40-50% of Nijmegen breakage syndrome patients have developed a malignancy by age 20 years, of which 85-90% are leukemias or lymphomas. The most common of these are non-Hodgkin lymphomas (two morphological subtypes predominate: diffuse large B-cell lymphoma, DLBCL, and T-cell lymphoblastic lymphoma, T-LBL), lymphoblastic leukemia (acute lymphoblastic leukemia, with both precursor B cells and T cells), and Hodgkin disease. [59, 60, 61, 62] Two cases of acute myeloblastic leukemia [63] and a single case of acute monocytic leukemia [64] were also reported.
Among solid tumors, 2 were observed relatively frequently: medulloblastoma in 5 patients [15, 65, 66] (further 2 cases unpublished) and rhabdomyosarcoma of the perianal region in 3 others. [67, 68, 69] The latter, rhabdomyosarcoma arising perianally, is extremely uncommon in children; therefore, taking into account the number of Nijmegen breakage syndrome patients with this type of cancer, a strong association with Nijmegen breakage syndrome is suggested. [69]
Other malignancies were present in single patients only. These included papillary thyroid carcinoma, gonadoblastoma, glioma, meningioma, neuroblastoma, and Ewing sarcoma. [3]
Cutaneous manifestations and hair characteristics
Skin pigmentation abnormalities include café au lait spots (usually 2-5 spots, irregular in shape) and/or depigmented spots, which are present in approximately half the patients. [3, 53, 4] In 3 Polish patients, vitiligo was observed by the time they became adolescents, with progression as they aged. Less frequently, sun sensitivity of the eyelids is observed, and, occasionally, cutaneous telangiectasia (particularly on the back) is seen. Multiple pigmented nevi and cavernous or flat hemangiomas can also occur.
Cutaneous, sarcoidlike granulomas were observed in two female Nijmegen breakage syndrome patients with accompanying ocular manifestations in one of them. [70] (Chrzanowska, unpublished data). Primary cutaneous tuberculosis and necrobiotic cutaneous granulomas were reported, respectively. [71, 72]
Usually, the hair is thin in infants and toddlers, but later, improvement is observed. Early graying of hair may be observed by adolescence.
Note the images below.

Other developmental anomalies
CNS malformations are observed relatively frequently and may be more common than expected. Small frontal lobes and narrow frontal horns of the lateral ventricles were documented in all patients who underwent cranial MRI. [73] Small brain size may be associated with other CNS developmental abnormalities, including partial agenesis of the corpus callosum, hydrocephaly, arachnoid cysts, and neuronal migration disorder (in the form of schizencephaly or pachygyria). [67, 73, 74]
Minor skeletal anomalies, such as clinodactyly of the fifth fingers and/or partial syndactyly of the second and third toes, are encountered in approximately half the patients. Hip dysplasia, preaxial polydactyly, and sacral agenesis are less common. Note the image below.
Urogenital defects noted in several patients with Nijmegen breakage syndrome have included kidney pathology (eg, agenesis or hypoplasia, ectopic single kidney or dystopic kidneys), hydronephrosis, hypospadias, and cryptorchidism.
Among other abnormalities, tracheal hypoplasia, cleft lip and/or palate, choanal atresia, anal atresia/stenosis, and cardiovascular defects (patent ductus arteriosus, ventricular septal defect) are reported. Polysplenia, a peculiarity with no clinical significance, is relatively frequently detected by ultrasonography.
Other complications
Two pediatric patients were reported to suffer from juvenile rheumatoid arthritis–like arthritis and chronic polyarthritis, respectively. [75, 76]
Complications
Recurrent pneumonia and bronchitis may result in bronchiectasis or respiratory insufficiency.
Recurrent otitis media may result in draining ear(s) or mastoiditis.
Malignancies occur frequently in patients with Nijmegen breakage syndrome.
An adverse reaction to radiation therapy, chemotherapy, or both in patients with unrecognized Nijmegen breakage syndrome may result in toxic death.
At least 3 patients who had medulloblastoma and received radiation before being diagnosed with Nijmegen breakage syndrome were fatally injured, and they eventually died from complications of the therapy. [15, 65, 66]
Alopecia was an adverse effect observed in a Polish patient with acute myeloblastic leukemia given an 18-Gy dose of cranial irradiation for CNS prophylaxis. However, another Polish patient manifested no complications after receiving an identical dose by prophylactic cranial irradiation for high-risk group T-cell acute lymphoblastic leukemia. Both patients were treated for the malignancy before the diagnosis of Nijmegen breakage syndrome was established (Chrzanowska, unpublished data).
Physicians should be aware of the possibility that Nijmegen breakage syndrome is underdiagnosed in children with malignant diseases in geographical areas where the disease is less frequent.
A high index of suspicion is necessary for patients who (1) develop any type of malignancy and have congenital defects (eg, microcephaly) and (2) develop lymphoid malignancy at a very young age (younger than 3 y).
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A 6-month-old infant with Nijmegen breakage syndrome. Note microcephaly, the slightly upward-slanting palpebral fissures, and small chin.
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Lateral facial features with sloping forehead and receding mandible are shown in a 6-month-old infant.
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Typical facial features in a 9-year-old girl with Nijmegen breakage syndrome. Note the markedly upward-slanting palpebral features.
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Lateral profile. This view shows a relatively long nose and receding mandible.
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Cutaneous sarcoidosis in a patient with Nijmegen breakage syndrome. Note syndactyly of the second and third toes.
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Vitiligo spots in a patient with Nijmegen breakage syndrome.
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Progressive vitiligo in a patient with Nijmegen breakage syndrome.
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Café au lait–like spots in a patient with Nijmegen breakage syndrome.
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Preaxial polydactyly of the hand in a patient with Nijmegen breakage syndrome.
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MRI in a patient with Nijmegen breakage syndrome shows large cerebrospinal fluid space that communicates with the left lateral ventricle and underdevelopment of the parietal lobes. Reprinted with permission from the Journal of Medical Genetics. Copyright 2001, BMJ Publishing Group.
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MRI in a patient with Nijmegen breakage syndrome. Note compression of the posterior fossa and the lack of cerebellar atrophy. Reprinted with permission from the Journal of Medical Genetics. Copyright 2001, BMJ Publishing Group.
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MRI in a patient with Nijmegen breakage syndrome. Note the small frontal lobes and the narrow frontal horns of the lateral ventricles. Reprinted with permission from the Journal of Medical Genetics. Copyright 2001, BMJ Publishing Group.
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MRI in a patient with Nijmegen breakage syndrome. Note the partial defect of the corpus callosum. Reprinted with permission from the Journal of Medical Genetics. Copyright 2001, BMJ Publishing Group.