|Year : 2012 | Volume
| Issue : 1 | Page : 42-44
Rubinstein Taybi syndrome: Broad thumbs - Hallux syndrome
Mahesh Kamate1, NS Mahantshetti2, Anshul Mehra2
1 Department of Paediatric Neurology, KLE University's J N Medical College, Belgaum, Karnataka, India
2 Department of Paediatrics, KLE University's J N Medical College, Belgaum, Karnataka, India
|Date of Web Publication||21-May-2012|
Department of Paediatric Neurology,J.N. Medical College, Belgaum, Karnataka
Source of Support: None, Conflict of Interest: None
The Rubinstein Taybi syndrome is a rare genetic disorder that is characterized by varying degrees of intellectual disabilities, distinct facial features, broad thumbs and first toe, and delay in cognitive and motor skill development. This is often detected in newborns because of the physical features that are apparent at birth. Correct diagnosis helps in the appropriate genetic counseling of parents. Here we report a case wherein the characteristic physical features led to the diagnosis of the Rubinstein Taybi Syndrome.
Keywords: Genetic counseling, genetic disorder, rubinstein taybi syndrome
|How to cite this article:|
Kamate M, Mahantshetti N S, Mehra A. Rubinstein Taybi syndrome: Broad thumbs - Hallux syndrome. J Sci Soc 2012;39:42-4
| Introduction|| |
Rubinstein Taybii syndrome (RSTS) is a rare congenital malformation syndrome characterized by facial abnormalities, broad thumbs, broad great toe, short stature, and mental retardation.  The syndrome is estimated to occur in one in 300000 - 10,00,000, depending on the population being studied. The Rubinstein Taybi syndrome is caused by microdeletion in the 16p13.3 gene encoding for transcriptional co-activator cyclic adenosine monophosphate response element binding protein (CBP). ,
| Case Report|| |
The proband was a 4-year-old boy, second issue, born to second-degree consanguineously married couple. The antenatal period had been uneventful. Both parents were of average intelligence and normal stature, with no ocular or facial abnormalities. The child was delivered at term gestation with a birth weight of 3000 g. The intranatal and postnatal periods were uneventful.
The child presented to us with delayed attainment of milestones, constipation since five months of age, deformities of feet, and repeated upper respiratory tract infections. The child had attained head holding at seven months and the subsequent achievement of milestones had been delayed in all domains. He started sitting at three years and at four years the child could not speak, stand, or walk. He had been having complex partial seizures for the past four months and was on clonazepam at 1 mg / kg for the same. The child had two normal siblings. There was no other significant contributing family history. A history of feeding difficulty since birth, was present.
On examination the patient was found to be underweight (11 kg - 69% of the expected weight), had a length of 96 cm, and an occipitofrontal circumference of 44 cm (< 3 S.D. of that expected for that age and sex). On physical examination, the child had a prominent nose with a bulbous tip, depressed nasal bridge, antimongoloid palpebral fissures, micro-ophthalmos, and malformed ears. Examination of the face and oral cavity revealed irregular teeth, high arch palate, short upper lip, and protuberant lower lip. Hands and feet showed broad great toes, thumbs, and persistent fetal finger pads. Skeletal deformities like congenital talipes, equinovarus deformity in both feet, and hyper extensible joints were also present. Multiple keloids / scars and hirsuitism and hypertrichosis, were also present. Ophthalmic examination showed bilateral glaucoma with optic disc changes. Nervous system evaluation revealed that the patient had hypotonia with global developmental delay and speech difficulties. The rest of the systemic examination revealed no abnormalities.
The child was worked up for global developmental delay with dysmorphism. Karyotyping was normal, as was the ultrasound examination of the abdomen. Echocardiography did not reveal any cardiac lesions. The psychological evaluation revealed a developmental quotient of 35%.
| Discussion|| |
The Rubinstein Taybi syndrome was first described by Dr. J. H. Rubinstein and Dr. H Taybi in 1963.  The Rubinstein Taybi syndrome is frequently recognized at birth or in infancy because of the striking facial features and typical abnormalities seen in the thumbs and great toes. Males and females are equally affected, and it does not appear to affect any particular race or ethnicity more than others.  Problems in early life include respiratory difficulties, feeding problems, poor weight gain, recurrent infections, constipation, skeletal deformities, and moderate mental retardation. Patients usually present with developmental delay, mental retardation, skeletal malformation, constipation, and repeated respiratory tract infection.
Important clinical features in RSTS  include hands and feet [broad thumbs with radial angulation (87%), broad great toes (100%), other fingers broad (87%), finger clinodactyly (62%), persistent fetal finger pads (31%), deep palmar crease between the first and second toes (33%), flat feet (72%)], cranium [microcephaly (35%), large anterior fontanel (41%), delayed closure of the fontanel (24%), frontal bossing (33%)], facial abnormalities [palpebral fissures slant downwards (88%), Hypoplastic maxilla with narrow palate (100%), small opening mouth (56%), prominent or beaked nose (90%), deviated nasal septum (71%), auricles low-set, malformed or both (84%), microgranthia (49%)]; ocular abnormalities [heavy eyebrows (76%), long eyelashes (87%), stenosis of the nasolacrimal duct (43%), epicanthal folds (55%), strabismus (69%)]; skin findings [(hirsutism (75%), capillary hemangioma (25%), keloid formation (22%)]; cardiovascular lesions [ventricular septal defect and patent ductus arteriosus, atrial septal defect, occur in one-third of the cases], genitourinary [cryptorchidism (78% of males), renal anomalies (52%)], and skeletal [scoliosis (42%), spina bifida occulta (47%)]. Postnatal onset of growth deficiency is common, as is the delay in the achievement of milestones. Average age for childhood milestones: Crawl 15 months, sit up 11 months, walk 30 months, monosyllables 25 months, toilet training 62 months.
Patients with this disorder have increased risk of developing cancerous and non-cancerous tumors as well as leukemia. 
The RSTS needs to be differentiated from the Pfeiffer syndrome, Apert syndrome, Saethre-chotzen syndrome, and Greig syndrome. The constellation of clinical findings in the RSTS usually suggest the diagnosis. 
It is usually caused by microdeletion in the 16p13.3 gene encoding for transcriptional co-activator (cyclic adenosine monophosphate response element binding protein CBP). , CBP is important for the control of gene expression during early embryogenesis and is expressed in specific cell types of the developing heart, vasculature, skin, lungs, and liver. However, at present the cause of RSTS remains unknown in approximately half of the patients. The Rubinstein Taybi syndrome is inherited in an autosomal dominant manner. , The Rubinstein Taybi syndrome typically occurs as a de novo event.  In a majority of cases, the index case is the only affected member in the family. The parents of most individuals with Rubinstein Taybi syndrome are not affected. The risk to the siblings of the proband depends upon the genetic status of the proband's parents. When the parents of the proband are clinically unaffected, the empiric recurrence risk for siblings is approximately 0.1%. Individuals with the Rubinstein Taybi syndrome rarely reproduce. Theoretical risk to the offspring is 10%.
Currently there is no known cure for RSTS.  However, treatments such as special education, occupational therapy, and behavioral therapy can help people to cope with the disorder. Management is usually supportive and tailored to the problem of each patient. Broadly it includes institution of an early intervention program and detailed evaluation of defects. Treatment of specific manifestations, such as, eye abnormality, hearing loss, cardiac defect, sleep apnea, constipation or cryptorchidism is also needed. Surveillance includes close monitoring of growth and feeding, especially in the first year of life; as also, routine evaluation of eyes and hearing.  Survival rate is good, many people with RSTS are able to live long healthy lives, but prognosis depends on whether or not life-threatening complications occur. Respiratory infections and complications secondary to congenital heart disease are primary causes of morbidity and mortality in infancy. ,
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