Synonym: ataxia-telangiectasia variant 1, Berlin breakage syndrome
Inheritance: autosomal recessive
Molecular defect: mutation in NBS1 (homozygous or double heterozygous required for disease)
Clinical features:
(1) growth retardation at birth
(2) short stature (small for age)
(3) progressive microcephaly
(4) sloping forehead
(5) prominent nasal root and nose
(6) receding mandible
(7) large ears
(8) upward slant of palpebral fissures
(9) decline in cognitive ability leading to mental retardation
(10) cellular and/or humoral immunodeficiency with recurrent sinonasal and pulmonary infections
(11) premature ovarian failure in females
(12) predisposition to cancer, especially malignant lymphoma. Other tumors include sarcomas, gliomas and medulloblastomas.
(13) radiation sensitivity
(14) irregular skin pigmentation
