Psychomotor development in Cri du Chat Syndrome

To the Editor: Cri du Chat Syndrome (CdCS) is a partial aneusomy resulting from a deletion of the short arm of chromosome 5. Clinical features include specific dysmorphisms, a cat-like cry, microcephaly and severe psychomotor retardation (1, 2). Little has been reported regarding the assessment of psychomotor development in children with CdCS (2–6). This is principally due to the rarity of this syndrome (1:50000 live births) (2). In addition, the available data on psychomotor development are not always comparable because of the different methods used or the limited number of development milestones examined. Breg et al. (3) in a study of 13 institutionalized adolescent and adult patients found an IQB20 in all individuals. None of the 34 Danish probands studied by Niebuhr (2) had a mental age of more than a 3-year-old child. An improved prognosis was reported in later studies. Data collected by Wilkins et al. (4) on 65 home-reared patients who were given special education, evaluated with Vineland Social Maturity Scale and Denver Test, suggested that many children could have attained the social and psychomotor level of a normal 5–6year-old child. This observation was confirmed by Carlin (5) in 62 home-reared CdCS individuals who had been the subject of precocious consistent educational intervention. Cornish and Pigram (6), in a study on 27 CdCS children using the Society for the Study of Behavioural Phenotypes questionnaire, found that the majority of them had acquired some degree of mobility, dexterity and communication skills, which also suggested that the syndrome might be viewed in a more optimistic light in newly diagnosed cases. In recent years, parent-support groups have provided an opportunity to collect and study a large series of children or young adults. There are several reasons for studying the development of children with CdCS. The first objective is to give parents a more accurate prognosis about psychomotor development, especially in the early period of life, after the diagnosis of CdCS has been made. The second goal is to provide pediatricians, general practitioners and other professionals with a more accurate delineation of psychomotor skills. The third purpose is to offer support to the families in coping with a severe mentally handicapped child. With the support of the Italian Cri du Chat Children Association a questionnaire was sent to 86 families in the Italian register (7–9). A total of 84 answered the questionnaire which included items concerning demographics, birth data, growth, clinical features of the syndrome, illness, hospitalizations and a separate section on psychomotor development. The questions on development consisted of a list of items based on the Denver Developmental Screening Test II (10). The Denver Test II was used because it is a quick multidomain screen with good sensitivity and specificity, is widely accepted by pediatricians (11, 12) and has been already used for the evaluation of developmental delay in other multiple congenital anomaly/ mental retardation syndromes (13). Moreover, the calculation in percentiles allows a rapid comparison of the development of the relevant patient with that of a large group of CdCS children and with the normal child population as well. The parents were asked to state at what age their child achieved each milestone. Not all the items were answered. When a question was not answered or when the parents could not exactly remember the age at which the milestone was achieved, the case was excluded from the data set of the specific skill. Only one questionnaire was filled in for each patient. Percentiles were obtained based on the number of persons having mastered the skill. The age range of achieving the milestone was recorded in block form for 95% of persons and divided into 25, 50 and 75% completion. The number of individuals varied for each skill and is recorded in parentheses. No fewer than 30 patients were included for each of the 25 items from each of the 4 main areas of development (gross motor, fine motor, speech and personal/social). The skills with less than 30 cases were not included in the chart (Fig. 1). Acquisition of new skills occurred from 2 months to 16 years of age. No previously achieved milestone was lost. Data were compared with 90% of normal children (10).