Weaver syndrome

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Weaver syndrome

Definition

Weaver syndrome is a congenital genetic syndrome associated with rapid growth beginning in the prenatal period as well as with a specific facial appearance and certain skeletal features. It has also been referred to as Weaver-Williams syndrome.

Description

Weaver syndrome was first described by Dr. David Weaver in 1974. A number of different symptoms occur in Weaver syndrome, however, it primarily results in rapid growth beginning in the prenatal period and continuing through the toddler years and into the elementary school years. It is also strongly associated with the bones developing and maturing more quickly (advanced bone age), a distinctive appearing face, and developmental delay. Babies often have a hoarse low-pitched cry.

Genetic profile

Weaver syndrome is for the most part a sporadic condition, meaning that a child affected by it did not inherit it from a parent. In a very few families, autosomal dominant inheritance has been reported, which means that both a parent and his/her child is affected by Weaver syndrome. The cause of Weaver syndrome is not known and the gene(s) that are involved in it have not been identified.

Demographics

Weaver syndrome is rare. About 30 to 50 cases have been published in the medical literature. It occurs in both males and females.

Signs and symptoms

Children with Weaver syndrome tend to have large heads. The faces of children with Weaver syndrome are usually very similar to each other, more so than to other family members, and include a round face, small chin, long philtrum (groove in the midline of the upper lip), large ears, and eyes that are father apart from each other than usual. Other common symptoms include hypertonia (increased muscle tone, tight muscles) as well as hypotonia (decreased muscle tone, "floppy" muscles) and a hoarse low-pitched cry in babies.

The excessive prenatal growth often results in the newborn being large with respect to weight, length and head circumference. The rapid growth continues through the toddler and youth years with the child's length and height often being above the 97th percentile, meaning that out of 100 children of the same age, the child is longer/taller than 97 of the children. There is very limited information on the rate of growth through adolescence and on final height, as most of the patients diagnosed with Weaver syndrome who have been reported in the medical literature have been children. In addition, given that the condition was first described 25 years ago, long-term clinical information is just becoming available.

There are a number of other features that have been associated with Weaver syndrome. The child may have difficulty extending elbows and knees completely, fingers and/or toes may be permanently flexed (camptodactyly) or have other problems such as overlapping fingers/toes or clubfoot , and the skin may appear loose. The child may have normal or delayed development; severe mental retardation is rarely seen. Speech may be delayed and when present, may be slurred. A child with Weaver syndrome may also have behavioral problems such as poor concentration, temper tantrums, which may be related to frustrations arising from communication problems, and obsessive and repetitive patterns of play.

Diagnosis

Diagnosis of Weaver syndrome is based solely upon clinical examination, medical history, and x ray data. There are no laboratory tests that can provide a diagnosis. The clinical criteria that are considered to be diagnostic for Weaver syndrome are excessive growth beginning in the prenatal and infancy period, a characteristic facial appearance, advanced bone age with the bones in the wrist being more advanced than other skeletal bones, metaphyseal flaring in the leg bones (the ends of the bone are wider than normal), and developmental delay.

There are many conditions and genetic syndromes that cause excessive growth, consequently, a baby and/or child who has accelerated growth needs to be thoroughly examined by a physician knowledgeable in overgrowth and genetic syndromes. The evaluation includes asking about health problems in the family as well as asking about the growth patterns of the parents and their final height. In some families, growth patterns are different and thus may account for the child's excessive growth. The child will also undergo a complete physical examination. The child will also be examined in terms of his/her facial appearance with special attention paid to the shape of his/her head, width of the face at the level of the eyes, and appearance of the chin and forehead. Besides measurement of the head circumference, arm length, leg length, and wing span will also be measured. Laboratory testing may also be done. A chromosome analysis (karyotype ) may be performed as well as testing for another genetic syndrome called fragile-X syndrome. The patient's bone age should also be assessed. Bone age is determined by x rays of the hand. It is known that a child's age can be predicted by the appearance of the wrist bones. In some cases the bones may develop or mature more quickly than normal, or in other words, the child's wrist bones appear to be those of an older child. This is referred to as advanced bone age. Advanced bone age is present in nearly every child with Weaver syndrome. It does not appear to result in other health problems. If the child begins to lose developmental milestones or appears to stop developing, metabolic testing may be done to evaluate for a metabolic condition called Sanfilippo syndrome. Developmental milestones refer to the skills infants and toddlers acquire as they get older, such as smiling, cooing, grasping toys, rolling over, walking, and talking.

Treatment and management

There is no cure for Weaver syndrome. However, the symptoms that cause problems can be treated and managed. Surgery may be used to correct any skeletal problems such as clubfoot or finger or toe problems. Physical and occupational therapy may help with muscle tone. Speech therapy may help with speech, and behavioral assessments and treatments may help with behavioral problems.

Prognosis

With appropriate treatment and management, children with Weaver syndrome appear to do well. Intellectually, most individuals with Weaver syndrome are normal. Weaver syndrome is not associated with a shortened life span.

Resources

BOOKS

Cole, Trevor R.P., N.R. Dennis, and Helen E. Hughes. "Weaver Syndrome: Seven New Cases and a Review of the Literature." In Congenital Malformation Syndromes. New York: Chapman and Hall Medical, 1995, pp. 267-280.