Zimmermann–Laband syndrome is a rare disorder characterized by gingival fibromatosis, abnormalities of the nose and/or ears, absence and/or hyperplasia of the nails or terminal phalanges of the hands and feet, hyperextensibility of joints, hepatosplenomegaly, mild hirsutism and mental retardation. The syndromic characteristics of Zimmermann–Laband syndrome are highly variable and complicated. This paper described a patient with Zimmermann–Laband syndrome with new manifestations and discusses the possible underlying genetic mechanisms.
Gingival fibromatosis (GF) is characterized by slow and progressive enlargement of the maxillary and mandibular gingiva. GF can be inherited and present as an isolated disorder (hereditary gingival fibromatosis (HGF)), or as a part of a syndrome . Zimmermann–Laband syndrome is one of the syndromes characterized by GF, abnormalities of the nose and/or ears, absence and/or hyperplasia of the nails or terminal phalanges of the hands and feet, hyperextensibility of joints, hepatosplenomegaly, mild hirsutism, and mental retardation. The condition results from autosomal dominant inheritance and involves a highly variable phenotype . In this study, the authors report on a patient with Zimmermann–Laband syndrome with new manifestations. They call for more alertness in the routine diagnosis and treatment of the syndrome and discuss its variable phenotype and possible underlying genetic mechanisms.
A 12-year-old girl was referred for the treatment of GF. Her parents and 7-year-old brother had no signs of GF. The patient was born after a full-term pregnancy to a 21-year-old mother and a 22-year-old father. Her mother recalled that she had a fever and took some antibiotic drugs and paracetamol during the early period of the pregnancy, but she could not remember the exact drugs.
The mother reported noticing the gingival enlargement when her daughter was 1 year old. It was severe and prevented tooth eruption; only a few deciduous teeth cusps were present in the dentition until she was 6 years old. The gingiva overgrowth resulted in serious masticatory, esthetic and speech problems as she developed and surgery was carried out when she was 7 years old. Retained deciduous teeth were extracted and gingivectomy was performed. The disease recrudesced not long after the operation, and worsened as she aged. At 12 years, the patient underwent another operation in hospital.
Examination of the face showed mild hirsutism, thick eyebrows, telecanthus, a bulbous nose and thick lips. The patient’s profile showed that both the maxilla and mandible were prominent. Anterior end-to-end bite was also observed ( Fig. 1 ).
Intraoral examination showed diffuse and severe gingival enlargement in the maxilla and mandible arches. The enlargement also involved the palatal gingiva and affected speech. The gingival enlargement was so excessive that only the occlusal surface could be seen for most teeth and the interproximal spaces between the teeth were widened and filled with overgrown gingiva ( Fig. 2 ). Macroglossia was also noted, and wide and deep fissures were found in the tongue.
A panoramic radiograph taken before the operation revealed mild resorption of the alveolar bone and wider than normal teeth interproximal spaces due to the GF. Five supernumerary teeth were found in the panoramic radiograph: two next to the maxillary right third molar; one next to the maxillary left third molar; one next to the mandibular right third molar; and one above the mandibular left third molar ( Fig. 3 ).
A posterior–anterior plain film was taken of the patient’s chest before the surgery. The film showed an abnormal shadow of the heart, which appeared to be overlapped by a mass lesion ( Fig. 4 ). To enable further diagnosis, the patient underwent a CT examination of the thorax and lung. Thin-section CT scanning revealed a triangular soft tissue mass in front of the aorta without enlargement of lymph nodes; the mass had a smooth, homogeneous density ( Fig. 5 ). The CT suggested the mass was benign, and it was diagnosed with thymic hyperplasia with the aid of a pediatric radiologist.
The patient’s physical and radiographic abnormalities led examiners to determine that she was not an isolated GF patient but a syndrome patient, so further examinations were carried out.
The patient appeared to present with mental retardation compared with children of the same age. When asked questions, her answers were vague and unclear, and her parents reported that she struggled with learning at school. Results of a WAIZS standard intelligence test indicated an intelligence quotient of 75. As 70 is the arbitrary dividing line which distinguishes the mentally handicapped from the educationally subnormal, the patient was diagnosed as having mild cognitive impairment.
Ultrasonic color imaging showed splenomegaly with a homogeneous echo ( Fig. 6 ): intercostal spleen thickness was 4.51 cm, subcostal thickness was 2.24 cm, and subcostal length was 2.73 cm. Normal spleen could not be detected subcostally.
Deformed terminal phalanges of the toes were found on plain film of the feet ( Fig. 7 ). The results of routine hematology and biochemistry tests were normal. The patient’s karyotype was 46, XX, and no abnormality was found in any chromosome ( Fig. 8 ).